Ecology, Distribution, and Food Habits of Spectacled Bears, Tremarctos ornatus, inPeru

Bernard Peyton

Journal of Mammalogy, Vol. 61, No. 4. (Nov., 1980), pp. 639-652.

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ECOLOGY, DISTRIBUTION, AND FOOD HABITS OF SPECTACLED BEARS, TREMARCTOS ORNATUS, IN PERU

ABSTRACT.-A study of the behavior and ecology of the spectacled bear, Tremarctos ornatus, in Peni revealed that they occur in all three ranges of the Peruvian Andes, with the majority in the "ceja de selva," or eastern slope of the Cordillera Oriental. As evidenced by feeding sign and contents of scats, 83 foods were confirmed in the diet of spectacled bears. These include insects, rodents, livestock, corn, berries, tree wood, bamboo hearts, palm frond petioles, 22 species of Bromeliaceae, 11species of Cacta- ceae, and the fruits of 31 species of trees. Spectacled bears feed predominately on bromeliad hearts, particularly during the months when fruits are not ripe. From Feb- ruary to July, when most of the fruits are ripe, the animals move to the sources of these preferred foods. Direct observations provided information on the bear's corn-eating behavior. Certain other behavioral activities, such as the building of tree nests, were confirmed. Humid forests between 1,900 and 2,350 m in elevation, and coastal thorn forests are preferred habitats when water is available. Spectacled bears enjoy the most protection in the saturated rain forests in the "ceja de selva" and in the seasonally occupied areas at the upper extreme of the animal's elevational range. The spectacled bear is not in immediate danger of extinction in Peru owing to its adaptation to a diversity of habitats and the difficulty of access to bear areas with more than 45-degree slopes.

The spectacled bear, Tremarctos ornatus, lives in a variety of Andean habitats from the Cordillera de Merida in Western Venezuela to Porta Province in Bolivia (Bridges, 1948; Walker et al., 1964; Erickson, 1966a). Walker et al. (1964) said the species prefers forested jungles, but that it can be found from 457 m to elevations exceeding 3,658 m. Spectacled bears have been described as ground feeders on fruits in the coastal desert in Peru (Osgood, 1914),or as tree climbers feeding on nuts and fruit stalks of palms in the mountain forests of Colombia (Tate, 1931).Captive Tremarctos ornatus prefer and do better on a diet of plant matter than on one of meat (Crandall, 1964; Davis, 1955). Surveys conducted by Brack (1961) and Crimwood (1969) indi-cated that the spectacled bear is adapted to a variety of habitats in Peru.

Otherwise, little is known; the objective of my study was to increase our under- standing of the biology of Tremarctos ornatus. I report additional information on its range, food habits, and preferred habitats based on 203 field days in Peni.

Thirty-nine areas were visited in Peni between August 1977 and August 1979. Field trips varied in duration from 2 to 28 days. During these trips, 739 bear signs, including 118 scats, were examined in a variety of habitats at elevations ranging from 200 to 4,170 m. Scats were collected and sun dried, and volumetric estimates of the food remains were made by water displacement. The elevational limits of the habitat types were defined from measurements of elevation taken for the indicator plant species of each habitat (habits as classified by ONERN, 1976).

To determine the concealing cover and food potential for each bear habitat, the plot system used by Mealey and Jonkel (pers. comm.) to evaluate grizzly bear habitat was adopted. For 254 of the 739 signs, a 20- by 20-m' plot was delineated with the sign in the center. Within each plot, the percentage of cover for all plant species was estimated. The ability of each habitat to provide the bear with food was determined by averaging the estimated cover values of all plants used as bear foods for all of the plots within each habitat. The availability of concealment cover was determined using the same methods. In this case, averages were taken for all plants over 1.5 m in height. The plot system was used in all of the bear habitats except in the humid forest,

640 JOURNAL O F MAMMALOGY Vol. 61, No. 4

Cordillera Occidental

Cord~llera Oriental

FIG. 1.-Distribution of Tremarctos ornatus in the three ranges of the Peruvian Andes. Areas occupied by T. ornatus are indicated by the stippled and solid black shading. Circles indicate the locations of field trips. Letters indicate: A, ceja de selva areas of the Cordillera Oriental; B, ceja de selva areas of the Cordillera Vilcabamba; C, ceja de selva areas of the Cordillera Central (Departamentos Amazonas, San Martin, La Libertad, and Huanuco); D, ceja de selva areas in the provinces of Tarma, Satipo, and Huanta (north to south, respectively); E, valleys of the Pampas, Apurimac, and Santo Thomas rivers; F, subalpine paramo area between Nevado Cham- parra and Cerro Alto Santa Cruz (Departamento Ancash); G, humid forest, elfin forest, and wet grassland areas on mountain tops (Departamentos Piura, Cajamarca, Lambayeque, and La Li- bertad); H, scrub desert, thorn forest, and steppe areas of the western slope of the Cordillera Occidental (Departamentos Piura, Lambayeque, La Libertad, and Ancash).

where dense vegetation made it difficult to delineate 400-m2 plots. In the humid forest habitat, I used a system of 2-km-long transects to estimate the coverage of food-producing trees. A stan- dard value for the canopy cover of a typical food-producing tree was averaged from 64 randomly selected trees greater than 20 cm in diameter at breast height (DBH) that showed evidence of feeding activity by bears. This standard was multiplied by the number of food-producing trees within 5 m of the transect line on each census. The percentage of food-tree canopy coverage is the proportion of food-tree cover on each transect area (20,000 mZ).

Feeding behavior was based on six separate observation periods totalling 5 h and 25 min.

Trefnarctos ornatus occurs in all three ranges of the Peruvian Andes (Fig. 1)with most of the population located between 1,825and 3,320 m on the eastern slopes of the Cordillera Oriental, and above 1,750 m in the Vilcabamba Range (Figs. 1and 2).

November 1980 PEYTON-ECOLOGY O F SPECTACLED BEARS 641

Tropical 17 _.,Subtropical 6's 9"s 6'-12s 13"- 13.5's

FIG. 2.-Habitat types occupied by Tremarctos ornatus in Peni. Shaded areas indicated by letter symbols represent elevations of habitat types that are occupied year round by spectacled bears. These shaded areas correspond to the shaded areas in Fig. 1. Cross hatched parts of the shaded areas indicate elevations of habitat types that are used seasonally by bears. Tropical habitat types in Pen3 extend from the Ecuadorian border to 12" S latitude, and subtropical habitats extend from 12 to 17" S latitude.

These habitats are called "ceja de selva" (eyebrow of the jungle) in Peni, and extend along the eastern slope of the Andes from Ecuador to the Bolivian border. The ceja habitats include high altitude grasslands above 3,200 m composed of species of Stipa, Poa, Festuca, and Calamagrostis, and humid to saturated rain forests below 3,200 m with annual precipitation ranging from 900 to over 7,000 mm (ONERN, 1976). The humid forests contain trees up to 30 m in height of the genera Podocarpus, Cedrela, Eugenia, Weinmania, and Alnus. Trees are fewer and stunted, and bamboo (Chusquea spp.) more abundant in the elfin forests above the humid forest habitat. These forests contain moss-covered trees 2 to 5 m in height of the genera Polylepis, Baccharis, Berberis, Alnus, Escallonia, and Buddleia. Bear sign was not found above 4,000 m in the Cordillera Oriental, nor on the western slopes of the Carabaya Range. Bears are reported to descend as low as 650 m in the wettest areas of the ceja, notably in the province of Sandia near the Bolivian border.

In the Cordillera Central, spectacled bears live in the humid forests above 1,800 m north of 10" latitude, and between 1,675 and 2,890 m in the provinces of Tarma, Satipo, and Huanta (Figs. 1 and 2). Vegetational characteristics of these forests are similar to those of the humid forests of the Cordillera Oriental and have an annual rainfall of 790 to 1,800 mm (ONERN, 1976). A small population of bears occurs in the thorn forest habitat between the towns of Ocros and Chulpi along the Pampas, Apu- rimac, and Santo Thomas rivers (Figs. 1and 2). Cereus sp. and Opuntia spp., Ama- r~llidaceae(Agave americana and Fourcroya andina), Puya sp., and Bombax sp. veg- etate the steep slopes, which often exceed 50 degrees. The average rainfall is 413 to

642 JOURNAL OF MAMMALOGY Vol. 61, No. 4

553 mm (ONERN, 1976).Bears are absent from the Cordillera Central south of Chulpi, and below 1,800 m on both slopes above the Rio Maraiion, which separates the Cor- dillera Central from the Cordillera Occidental.

In the Cordillera Occidental, Tremarctos ornatus inhabits a small area of steppe habitat and subalpine paramo on the northern border of Huascaran National Park between Nevado Champarra and Cerro Alto Santa Cruz (Figs. 1 and 2). The steppe contains grasses (Poa sp., Stipa ichu, S . brachiphylla, Calamagrostis enimens, C . escunarum, and Festuca dolichophylla), cacti such as Opuntia subulata, bromeliads (Puya spp. and Tillandsia spp.), and trees (Eucalyptus globulus and Schinus molle). The same genera of grasses are present in the subalpine paramo along with Lupinus spp., Hordeum muticum, and stunted trees such as Buddleia coriacea and Polylepis incana. Between the northern limits of the Huascaran National Park and the Ecua- dorian border, bears inhabit mountain tops that are surrounded by human populations and deforested land. These areas are characterized by tall forests, beginning at 2,345 m, which gradually become more stunted and wetter as the altitude increases until a natural grassland replaces them at elevations of 2,900 to 3,200 m. These habitats are similar to those on the eastern slopes of the Maraiion valley. Spectacled bears also occur in the scrub desert and thorn forest habitats of the western slopes of the Cor- dillera Occidental from the Pativilca River (10°42'S)northward to the town of Canc- haque (5'24's). The majority of this population lives in the steep slopes and canyons surrounding the Pativilca, Huarmey, Santo, Vini, and La Leche rivers. These bear populations are separated from each other, and from other such populations in the Cordillera Occidental, by human populations found along the coastal rivers and in mountainous terrain having sufficient precipitation to support year-round communi- ties (>500 mm annually). The human-disturbed areas in the mountains begin at 2,750 m at the southern end of the coastal bear habitat (Fig. 2) and 1,675 m at the northern end, and extend to a maximum elevation of 4,400 m in the Departamento Ancash. Trees such as Capparis angulata, C . oualifolia, and Prosopis limensis characterize the floodplain flora of the scrub desert from 200 to 900 m. The upper elevations of the bear-inhabited portion of the scrub desert are composed of 12 to 40" slopes covered with trees of Bursea graueolens, Loxopterygium huasango, Caesalpinia tinctoria, and Cordia rotundifolia; cacti of Cereus and Trichocereus spp.; and Tillandsia spp. Trees in the thorn-forest habitat, which occurs between 1,400 and 2,200 m, consist of 10-m-high Bursea graveolens, Ficus spp., Bombax discolor, Acacia sp., Geoffroya striata, and Caesalpinia corymbosa. The branches of these trees are often thickly covered with Tillandsia usneoides and T. barbata.

The spectacled bear is absent from the thorn forest and dry forest habitats along the road from Chiclayo to Bagua; along the Chamaya, Chinchipe, and Huancabamba rivers; and from the Cordillera Occidental south of the Pativilca River.

Food Habits Feeding sign and scats made up 75.6% of the field evidence (Table 1)from which

83 foods were identified as eaten by spectacled bears. Seventy-six of the foods were plants. The Bromeliaceae were most important, making up 46.8% of the feeding sign and including 22 species of the genera Puya, Tillandsia, and Pitcarnia. These plants occur throughout the bear's range in Peni, except in the coastal scrub desert habitat below 450 m. During the months when fruits are not ripe or in areas where fruits are not available, bears feed almost exclusively on the succulent hearts of bromeliads, and climb trees to eat those adhering to the trunk and branches. Bears also climb rocks to eat clinging Tillandsia spp., Puya herrarae, P. cerrateana, and P. densijora. As with fruit-bearing plants, individual bromeliads showed signs of partial consump- tion. While feeding, bears may bypass a plant growing close to the one just eaten to

643 November 1980 PEYTON-ECOLOGY OF SPECTACLED BEARS

TABLE1.-Frequencies and percentages of field euidence of spectacled bears in Peru'. The euidence was gathered during 203field days between August 1977 and August 1979, and was found in all habitat types containing bears described in Fig. 2 .

Sign Frequency Percent

Eaten plant parts Bromeliaceae Palm frond petioles Corn (Zea mays) Orchidacea bulbs Bamboo (Guadua sp.) Amaryllidaceae Tree wood (Bombax discolor)

Climbed and eaten cactus Climbed trees (Bombax discolor) Climbed trees for fruit Scats Tracks, diggings, torn logs Markings on trees Day beds on the ground Day beds in trees Nests in trees Direct observations

Total

select another farther away. In the scrub desert habitat, bears often drag cacti and large Tillandsia into nearby caves, possibly to avoid detection and the mid-day heat. Because bromeliads can contain as much as a liter of water, they may be a valuable water source in the scrub desert and steppe habitats. Cliff-adhering bromeliads also serve as climbing aids on steep slopes.

Although the feeding method was not observed, remains of eaten bromeliads and information provided by local inhabitants indicate that the white central portion is eaten. On large bromeliads, bears tear off individual leaves or bunches to eat the white bases, often using both paws to spread the leaves. The edible hearts of the smaller bromeliads are exposed by ripping the entire plant off its substrate. No doubt the strong masticatory adaptations Davis (1955) mentioned are useful on the tough Puya. On the softer Tillandsia, the inner column of leaves was often pulled out in one piece and the base chewed off.

The pulp and fruit of 11 species of cacti were identified as foods, and composed 7.5% of the feeding. sign. Bears depend on cacti in the driest zones of their range, notably in the coastal scrub desert between 7.5 and 9" S latitude, and in the higher elevations of the thorn forest habitat along the Rio Pampas where they feed on fruits of Opuntiaficus in February. Although cacti are abundant north of 7.5" S latitude, few had the deep scars left by climbing bears, probably because of the increased avail- ability of fruiting trees in this more humid zone. Cacti such as the shuyamo were observed to have been climbed to a height of 7 m to reach the fruits at the top. In the driest desert habitat with an annual precipitation of less than 250 mm, spectacled bears eat the pulp of Trichocereus pachanoi, Cereus macrostibas, and an Echino-cactus sp. called melon del oso (bear melon), possibly for their water content. In the steppe habitat south of the Rio Vini along the coast, near Ocros on the Rio Pampas, and in Cusichaca on the Rio Urubamba, bears will occasionally eat the bases of the leaves of Agave americana and Fourcroya andina (both Amaryllidaceae). Local inhab- itants on the coast and along the Rio Pampas claimed that bears eat the honey pellets

644 JOURNAL OF MAMMALOGY Vol. 61, No. 4

made inside the dried Agave poles by a large black bee. I examined three of these poles that had been tom open by bears, but found no conclusive proof of the bear's intentions.

Thirty-one species of fruiting trees, representing 28.7% of the feeding sign, were identified in the bear's diet. These trees generally occur between elevations of 450 and 2,350 m. Above 2,350 m, Tremarctos ornatus depend more on bromeliads, orchid bulbs, Ericaceae, palm frond petioles, young green shoots of kurkur (Chusquea scan- dens), and stalks of young bamboo up to 7 cm in diameter (Guadua sp.). Care was taken to distinguish sign left from the climbing of a tree for its own fruit from sign on those trees climbed for a bromeliad or to bed in. The fruits most freauentlv eaten were Ficus spp. In the coastal scrub desert, Ficus spp. dominate the more humid ravines around water holes and provide cover for traveling bears. Of 64 trees climbed by bears in one humid forest in Shipasbamba (Departamento Amazonas), Ficus spp. were well over a meter in DBH and over 25 m in height, as opposed to other genera of fruit-bearing trees whose DBH and height averaged 45 cm and 16.5 m, respectively. Twenty-five of the measured trees had been climbed repeatedly over the years as indicated by the healed scars in the bark, suggesting that spectacled bears may define their home ranges around known groves of trees. To reach the first branches of the enormous fig trees (Ficus spp.), bears will sometimes climb vines or nearby trees with diameters that are often no wider than the width of the animal's paws, or take advan- tage of the vines and aerial roots that wrap around the tree trunks.

Spectacled bears also eat the leaf petioles of three Palmacea in the humid forest habitat, first flattening the leaves of a young palm that has not yet grown a trunk, and then ripping off the leaves to chew the base of the petiole. Palms with petioles less than 2 cm in diameter are often ripped out of the ground and then eaten. Feeding sign on chonta, chontilla, and palmera vicuna (Ceroxylon sp.) were noted between the elevations of 1,860 and 2,758 m. Similar sign on Ceroxylon sp. in Colombia was reported by Tate (1931). Palm petioles were eaten mostly in trace quantities by trav- eling bears and constituted 9.7% of the feeding sign.

In the coastal scrub desert habitat, the spectacled bear tears the bark off the pasallo tree (Bombax discolor) and eats the cortex. Either the bear s t r i ~ s the bark off at the base 'of the trunk, or the animal will climb the tree and strir, axbranch 6 to 8 cm in diameter. Most of the pasallo trees that were climbed by bears displayed claw marks going no further than the first horizontal limb. The limbs of the pasallo tree are host to a dense covering of Tillandsia barbata and T. usneoides, both of which are some- times eaten by bears. Hunters and local campesinos say the bear prefers to sleep on this soft bed and that the bromeliads easily camouflage its presence.

Nest building in trees and on the ground was reported by Bridges (1948), but the use of the nest was not understood. Five nests in trees were found in Peru during this survey. One was found in a molle tree (Schinus molle) at 1,100 m in the coastal scrub desert habitat of Pararin (~epar tamento Ancash), another h a s located 15 m up a ciruelo tree (Benchesia sp.) in a humid forest at 2,100 m in the Departamento Amazonas, and three nests were found in another ciruelo tree in the same area. In feeding situations where the fruit-laden branches will not support a bear's weight, the animal will climb as close to the fruit as possible and then pull the branches toward itself. Branches up to 5 cm in diameter are broken in this fashion. After eating the fruit, the bear will reposition itself on top of the platform made of broken branches in order to reach branches farther away. These platforms crudely resemble large nests; campesinos say they are used for day bedding.

Day beds on the ground in the humid forest consist of oval bare spots 20 to 45 cm long, situated in a depression between the roots of a large tree such as a monte cedro (Cedrela sp.) or tajupe (Ficus sp.). Four day beds were found in the moss covered

--- - -

645 November 1980 PEYTON-ECOLOGY O F SPECTACLED BEARS

TABLE2.-Frequencies and percentages of the total volume of food items identijied from 118 bear droppings found in Peru' at elevations between 396 and 3,478 m.

Food items Frequency Percent

Bromeliacea hearts Tillandsia sp., Puya sp., Pitcarnia sp.

Cactacea fruit and pulp Cereus sp., Trichocereus sp., Opuntia sp.

Tree fruits Capparis angulata Capparis oualifolia Ficus spp., humid forest Ficus spp., scrub desert Cecropia sp. Schinus molle Benchesia sp. Cordia rotundifolia unidentified "tumbe" unidentified "pucamura"

Tree wood Bombax discolor

Palmacea frond petioles Ceroxylon sp.

Shrub berries Pernettya prostrata, Caoandishia spp. Physalis peruoiana

Orchidacea bulbs Epidendrum sp., unidentified "ccochiccha"

Crops Annona cherimolia Zea mays Saccharum officinarum Cucurbita maxima

Insects (4 spp.) Honey bee hive Animal (4 spp.) Unidentified plants

Total

* t = less than 0.5%.

branches and on the trunks of trees that the spectacled bear had recently fed in. In the coastal scrub desert, bears bed by day under boulders in ravines, usually within 10 m of a water hole. Day beds beneath roots or in caves were found below cliffs in the thorn forest habitat and in the subalpine paramo habitats. Scats were normally found in or within 5 m of a day bed.

Scat Analysis

Bear foods were confirmed from the content of 118 droppings as well as from feeding signs. The occurrence and percentage of the total volume for each food item is listed in Table 2. Fifty-three percent of the scats were found in ravines indicating how important this topographical feature is for providing the essentials of bear survival. More than half of these scats were found less than 5 m from a water source. The volume of each scat varied between 0.06 1and 1.73 1, and 56.7% of all scats contained only one food item.

646 JOURNAL O F MAMMALOGY Vol. 61, No. 4

TABLE3.-Data on the seasonality of the spectacled bear diet in Peni. X indicates the months during which bears ate the food items, confirmations on the months when food items are eaten were based on direct obsemations of feeding bears and fresh field evidence less than 2 weeks old; r indicates the months when food items were reported to be eaten b y bears and when the food items were observed in an edible condition i n the field. In the case of animal foods, r denotes the months during which the animals grazed within 100 m of bear sign and are reported to be eaten.

Months

Food item J F M A M J J A S O N D

Bromeliaceae Scrub desert habitat r X X r X X r r X X X r Humid forest habitat r X X X X X X r r r r r Subalpine paramo habitat r r X X r r r r r

Palm frond petioles Bamboo (Guadua sp., Chusquea sp.) X

X X r X

X r

X X

r r

r X

X

Orchidaceae bulbs r X r X Tree wood (Bombax discolor) X

Tree fruits Capparis spp. X X X Schinus molle r X X Znga feuillei Ficus spp., below 1,500 m Ficus spp., above 1,500 m

r X X X

X X X

r X X X r r X

Carica candicans r X r r r r r Amburana caerensis r r r X Sideroxilon sp. X X Cecropia sp. X X Benchesia sp. r X X Cordia rotundijolia Eugenia sp.

r r r X r r

Lucuma sp. X X X

Unidentified tree fruits "Tumbe" X r X "Remo Caspi" "Monte aceituna" X X

X r X

"Huiyuntoy" r r "Bariagas" "Pucamura"

r X

Shrub berries Vacciminium ftoribundum X r X Cavandishia spp. r r r r r Rubus spp. Pernettya prostrata

r r

r X

r r

r X X

Physalis peruviana X X r

Cactaceae fruits and pulp Echinocactus sp. Trichocereus pachanoi

X X X

Cereus macrostibas r r x r Opuntia ficus Mammalaria sp.

X r X

Amaryllidaceae Agave americana X r r Fourcroya andina

Crops Zea mays Saccharum officinarum

r X X X

X X X

Annona cherimolia r X r

November 1980 PEYTON-ECOLOGY OF SPECTACLED BEARS

Months

Food item J F M A M J J A S O N D

Cucurbita moschata Lucuma obouata

Insects, honey Animals

X r X X r X

Rodents Odocoileus uirginianus Cows, goats

r r

X X

X X

r

X

r r r r r

r r r

Non-plant items made up 4.1% of the total scat volume and included the remains of deer, cow, goat, rodents, caterpillar nests, beetles, bees, and honeycomb. There is some question whether the large animals eaten by bears are killed by them or are consumed when found as carrion. Tschudi (1844) mentioned that bears preyed on deer, guanaco, and vicufia. I examined the hide of a woolly tapir (Tapirus pinchaque) that showed the blunt scars from a bear attack. Campesinos reported that they found the wounded animal in a ravine at 2,200 m near Huambos (Departamento Cajamarca) and lassoed it. In addition, I examined 14 hides of livestock kills blamed on spectacled bears. Nine displayed the more arched paw mark and thinner scratches of puma. According to Erickson (1966b), bears are blamed for cattle kills because of the bear's carrion eating habits. The reputation spectacled bears have as a meat eater is probably due to the habit of sport hunters and campesinos to anthropomorphize the bear and to attribute the feeding behavior of a few livestock-eating bears to all large male bears.

The diet, facial and hide coloration, and behavior of spectacled bears are so varied that campesinos and some local biologists believe that there are several species in Peni. The plant-eating bear is called oso achupallero (achupalla bear), yura matteo (white-fronted bear), or yanapuma (black puma). The cow-eating bear is called oso ganadero, ocumari, and puca mate (red-fronted bear). The last term is reported to refer to the blood stain on the bear's muzzle, but this bear is most often seen in the sub- alpine areas of southern Peru during the season of ripe fruit of Ericaceae, which could also stain the bear's muzzle red.

To kill a cow, bears are reputed to pursue the animal on steep slopes or near a cliff to make it fall. In cases where the cow does not fall on its own, the spectacled bear purportedly grabs the head and twists the neck until the cow falls.

Seasonality of Foods and Direct Observations

Spectacled bears show a preference for the berries, cactus fruits, and tree fruits listed in Table 3. Most of the trees produce fruit after the winter rains that fall between November and March, with the heaviest rainfall occurring in December and January. Throughout Peni, spectacled bears are reported to give birth during the months of heaviest rainfall. Cubs are most often seen with their mothers during the first 3 to 4 months of their development, which coincides with the season of fruit abundance. This season varies according to the altitude and slope aspect of the habitats and yearly fluctuations in the weather patterns.

In the low coastal scrub desert, bears follow the cycle of ripening fruits starting with sapote (Capparis angulata) and bichayo (Capparis ovalifolia) in February, fol- lowed by molle (Schinus molle) and figs (Ficus spp.). The latter ripen as late as May at upper elevations of the thorn forest, and July in the humid forest. Ravines provide travel routes through protective cover to the desert pampas below 600 m where Cap-

648 JOURNAL O F MAMMALOGY Vol. 61, No. 4

paris spp. offer less than 5% cover in which the bear can hide. Campesinos reported that bears are active in these areas in the early morning and late evening, returning to the ravines to bed between 0830 and 1630 h. The vulnerability of bears in areas having little concealing vegetation and the higher density of bears during the ripe fruit season of Capparis spp. account for successful hunts and exaggerated population estimates.

On 27 March 1978 at 1615 h, I frightened a bear (+90 kg) out of a ravine in Cerro Chaparri, Departamento Lambayeque. The bear had recently fed on pasallo wood and sapote fruits. After climbing out of the ravine to the top of a large rock, the bear circled to smell for the direction of the intrusion, returning each time to the large rock. It then descended into the ravine, and using the topographical feature as cover, escaped to the cliff terrain in the thorn forest habitat where I was unable to follow it.

What appeared to be the same bear was seen 1.5 months later in the thorn forest habitat, approximately 25 ground km north of the first sighting. The fruit season was past and the water holes in the scrub desert had dried. Bears were then subsisting entirely on bromeliads, which were growing mainly on rock cliffs. The animal was prompted to come out of a ravine 200 m from the recently torn-up remains of over 70 large (spikes 175 cm long) Tillandsia sp. The same sniffing behavior was observed and again the bear escaped using the cover of the ravine and the steep topography of the cliffs. Without these cliffs, the bear population would most likely have disappeared from the scrub desert and the thorn forest 30 years ago. Bears feed on bromeliads for the remainder of the year except for the mid- to late-summer consumption of overo (Cordia rotundifolia) and mitu (Carica candicans).

In the thorn forest of the Apurimac and Pampas rivers, bears feed year-round on leaves of Puya sp., Agave americana, and Fourcroya andina. Hunters claimed that prior to 1968 it was possible to see as many as nine bears feeding at one time on tuna (fruits of Opuntia ficus) in February above the steep slopes bordering the rivers. Today the bears are frightened away from the Opuntia groves by people who collect both the fruit and the cochineal worm (Coccus cacti) that lives on the cactus, and by the presence of livestock feeding in the groves. These bear populations would have disappeared if humans were able to descend the steep slopes or navigate the rivers. Occasionally bears kill livestock and raid corn (Zea mays) and sugar cane (Saccharurn officinarum) crops near the steep habitat, but the local inhabitants say that the majority of the bears eat bromeliads and the chuna cactus fruits, which are ripe in October.

In the humid forests, the highest concentrations of bears occur during the season of ripe corn (February-May), and during the fruiting season of ischpingo (Amburana caerensis), ciruelo (Benchesia sp.), chan chan (Cecropia sp.), and tajupe (Ficus sp.). Hunters take advantage of the fruiting cycles of these trees and may use dogs to trail and tree bears.

On 11June 1978, a small sow weighing approximately 20 kg was observed at 1500 h near Huambos (Departamento Cajamarca) feeding in a tajupe tree. In contrast to bears in the desert, those in the forest are active throughout the day. Some evidence was gathered on the number of trees a bear climbs in a day. One tajupe tree with fruits 8.5 cm in diameter could supply a large spectacled bear with food for at least 4 or 5 days. Forty-seven chan chan trees were climbed in April by a bear within 3 days as indicated by the freshness of the sap exuding from the claw marks. The flower pods, containing a sweet gum, and the stringy fruit had been eaten.

Throughout its range, bears habituated to eating corn move to the cornfields at the lower elevations (1,500-2,000 m) in March, and follow the ripening corn to the higher elevations (2,000-2,700 m). The most commonly raided cornfields are found in the ceja de selva (Fig. l ) , where they are on 30 to 40' slopes and are bordered by dense forests of charamosqua (Chusquea spp.) and tall trees, which offer excellent cover.

649 November 1980 PEYTON-ECOLOGY OF SPECTACLED BEARS

I observed bears feeding on corn three times. In all three instances the animals entered the cornfields during mid-day. Local campesinos claimed that bears prefer to enter cornfields before the first sunlight strikes the feeding area and in the afternoon from 1600 to 1800 h. Campesinos also reported that bears make daytime raids on cornfields during rainstorms, taking advantage of the absence of humans. During a rainstorm on 6 May 1979, I saw a sow weighing approximately 90 kg in the chara- mosqua bordering a cornfield in Incatambo (Departamento Cuzco). I watched her for half an hour as she sniffed from the protective cover above the cornfield, which later she entered at 1205 h. On entering, the sow climbed a fallen log to sniff the air before moving another 10 m into the cornfield. Rising up on her hind legs, the sow picked an ear of corn with both paws, placed it in her mouth, and carried it back to the place where I first saw her. She cleanly removed the kernels from the cob, which was held in both paws. The sow then waited 4.5 min and reentered the field for another ear. This sequence was repeated four times before the rain stopped and laborers returned to the field.

The other two observations were made on 12 and 13 July 1979 in a cornfield at 2,010 m owned communally by the settlements of Hapu, Quico Grande, and Queros. It is common for villagers in the subalpine paramo above 3,000 m to have communal cornfields and to provide people to guard them against theft and bear raids.

A large bear of approximately 120 kg entered the cornfield on 12 July at 1225 h, despite the presence of blue plastic flags on poles that had been placed on the perirn- eter of the cornfield to frighten bears. Like the behavior of the first bear I saw eating in a cornfield, this bear moved to a rock higher than the surrounding corn to sniff the air, and then ate four ears in 20 min before the crop guards chased it away. The crop guards then cleared back the brush for 5 m along the edges of the cornfield and burned rubber on the ground at the bear trail entrances. The next day a fire was lit in the middle of the field, but what appeared to be the same animal entered at 1115 h only 35 m from where it had entered the day before. During the 20 min of yelling on the part of the crop guards, the animal ate three ears and carried another into the forest. I followed the fresh tracks in the forest 2 h later, and discovered that five ears of corn (one freshly eaten) had been carried to a point some 200 m above the cornfield. The campesinos reported that sows will carry corn back to cubs that are too small to feed in the fields.

On examining 25 cornfields raided by bears, I found that the majority of the feeding sign was within 1 m of cover, usually along the uppermost edge of the field. Piles of husks and eight to 10 cobs marked these sites. In 20% of the cornfields. bears had -eaten approximately half of the crop. The entire corn crop was consumed by bears in three fields; each field represents half the annual food production of the owner. Farmers often try to get hunters to wait in their fields. One hunter in northern Peni killed 11 bears using a system of sending out notices to campesinos telling them he would pay them a reward for advising him when the bears were feeding in their cornfields. The cornfield where I saw the sow on 6 May showed the vulnerability of a corn-habituated bear during its feeding raids. During the past 10 years, six bears have been killed in this cornfield, the last in April 1979. According to local reports, males are often present with sows, and sometimes with yearling cubs and sows, during the months when corn ripens. In 1959, a hunter shot a male that had entered the same cornfield with two sows, each with two cubs. The male measured 206 cm from the nose to the tip of the tail and the eviscerated, unskinned carcass weighed 175 kg.

Spectacled bears normally eat corn 2 weeks before it is ripe. If a bear has not been frightened out of a cornfield it will likely return the next day. Otherwise it will feed on forest fruits and bromeliads or go to a different cornfield. A bear often returns 2 to 10 days later to the field where it was frightened. Bears are reported to reenter corn-

650 JOURNAL OF MAMMALOGY Vol. 61, No. 4

fields after the harvest to seek overlooked ears. I gathered no evidence of nighttime feeding by bears.

After the corn season has passed, bears will continue to eat tree fruits, bromeliads, orchid bulbs, and palm-frond petioles in the humid forest above the fields. This habitat is either occupied by humans or has been cut down below the cornfields in most of the Peruvian Andes. In all surveyed areas of the ceja de selva occupied by bears, there was a bear trail that ran along the ridge line through wet elfin forests to the grasslands of the high montane rain forests and subalpine paramo habitats. On the grasslands, bears eat bromeliads and Ericaceae such as Cavandishia weberbaueri, C . panculata, Vacciminium jloribundum, and Pernettya prostrata as well as the tree fruits of huiyuntoy and bariagas. In areas where there are no signs of humans and livestock, tracks and feeding sign indicate that bears roam freely away from cover. Where humans are infrequent visitors and cattle excrement is present, bears will penetrate the grasslands by way of vegetated ravines and stay within 1m of cover or along a cliff edge. Campesinos reported that bears roam the open pun0 during the rainy months of November to February. Some cattle are reportedly killed during this time by bears that are taking advantage of the absence of shepherds who dislike the wet weather and cold temperatures of 6°C.

Local Accounts and Folktales

Although local accounts of spectacled bear behavior may have a factual basis, they are often filled with fantasy and conjecture. Throughout Peni, reputable sources said the bear hauls its livestock kills up a tree to eat in seclusion and protect the kill from foxes. Bears are also said to climb trees above cornfields to scout prior to feeding. I found six trees that had recently been climbed, situated above the cornfields where I had observed bears. If these trees had been climbed for scouting purposes, it was unclear whether they had been climbed before the bears entered the cornfield or after. One of the trees contained a day bed with a half eaten rat and a scat in the bed. The scat contained bear hair, rat hair, corn, and bromeliad leaves. The evidence indicated that bears eat some meat while in a tree and that the animal had climbed the tree after at least one corn raid.

Local informants claim that "old" bears (large and often mistaken to be old) wait 30 to 90 min before entering a cornfield and position themselves so that they can always see the footpath leading to the field. Inexperienced bears (small and young) were said to enter without caution and were reported to be the ones that were most often shot. The large bears that I observed in the cornfields entered cautiously without the knowl- edge of human presence, and boldly while crop guards tried to chase them away from a distance of 40 m. With the exception of the small sow I observed in a tajupe tree, all the other bears I observed moved slowly about the difficult terrain, even after they had detected human presence. When surprised, spectacled bears are reported by campesinos to escape by rapidly rolling downhill. Cubs are said to escape by climbing onto their mother's back.

Habitat Quality

Habitat types were judged for the availability of food, concealing cover, water, and seclusion. The study of individual plots indicated that the thorn forest and humid forest are the best habitats for bears in Peni from the point of view of food and the availability of concealing cover (Table 4).The coastal thorn forest is a better habitat for bears than is the thorn forest of the Cordillera Central. Water may become un- available in the thorn forest of the Cordillera Central from April to September, and bears must descend to the Apurimac and Pampas rivers to drink. Seasonally available foods are more abundant in the coastal thorn forest habitat where fruit-producing trees

November 1980 PEYTON-ECOLOGY OF SPECTACLED BEARS 651

TABLE4.-Percentage coverage of plants comprising bear foods and cooer for habitat types described in Fig. 2. Data were taken from 254 plot studies made between the elevations of 335 and 4,170 m. Trace coverage (less than 0.5%) is indicated by t .

% of food coverage Total % of

Habitat type Plot elevations

( 4 Fruits Cactus Brome-

liads Berries food

coverage hiding

coverage

Tropical Scrub desert 9"s Scrub desert T30'S Scrub desert 6"s Thorn forest T30'S Thorn forest 6"s Low steppe 10"s High steppe 10"s Subalpine paramo 9"s Humid forest 5"301S Elfin forest 6"s Humid grasslands 6"s Elfin rain forest 5"30"S

Subtropical Thorn forest 13"301S Subalpine paramo 13"301S Elfin rain forest 13"s

provide up to 21% of the cover in the coastal ravines and 6% at the base of cliffs. Sixty-seven percent of the field evidence I found in coastal thorn forests was from ravines and bases of cliffs, topographical features that provide the bear with water holes during the dry season, and dens and protection in steep terrain. Cliffs can contain up to 25%cover of Bromeliaceae, thus assuring the bear a food source when fruits are not ripe.

Thirty-nine percent of all bear sign was found in humid forests between 1,900 and 2,700 m. These forests were relatively free of dense underbrush and the height of the tree canopy exceeded 15 m. The 2 km of transects walked in the humid forest habitat contained 614 trees with DBH larger than 20 cm within 5 m of the line of travel. Of the total surface area (20,000 m2) represented by the transects, 54% was covered by 214 trees that produce bear foods. The 54% figure is a low estimate for the food coverage of the transected area because the method did not measure the quantity of bromeliads, orchids, palms, bamboo, and other plants that provide bears with food. Bear trails were concentrated within 100 m of a stream. Bear hails between ravines were often aligned with the fall line of the slopes. The steepness of the slope did not inhibit havel, although bears tended to travel in areas where the undergrowth was open. The densest vegetation, elfin forest, occurs above the humid forest zone be- tween 2,500 and 3,600 m, where bamboo (Chusquea spp. and Guadua sp.) makes up as much as 92%of the vegetative cover. Only 4%of the bear sign was in this habitat. Bears traveling through elfin forest habitats feed on bamboo, bromeliads, and palm- frond petioles.

In the other habitat types, bear populations are limited by scarce food sources and inadequate cover. These conditions prevail in the extremes of the elevational range of the species. In the scrub desert between 200 and 600 m, and in the subalpine paramo of the Occidental Andes above 3,800 m, food-producing plants make up less than 2%of the cover. These two habitats offer practically no other concealment than topography and only seasonally support populations of bears. Bears move to the thorn forest and grasslands (2,000-2,900 m) as the water holes in the scrub desert dry up in

652 JOURNAL O F MAMMALOGY Vol. 61, No. 4

May. The usage of the subalpine paramo habitats by bears is dependent on the ab- sence of humans and the ripening of tree and ericaceous fruits. The average cover values of these food plants in the subalpine paramo habitats indicate that these foods may be more abundant in southern Peni (2.4% average cover) than in northern Peni (<I% average cover). Bears use the steppe (grassland) habitat and adjacent elfin forests from April to September. For protection and concealment during these months, bears in the steppe habitat must rely on deep steep-sided ravines, and other terrain avoided by humans. Cactus foods are most common in the steppe habitat between 3,150 and 2,900 m, but these have only seasonal importance.

From the aspect of seclusion, spectacled bears are most secure in the inaccessible rain forests of the ceja de selva. The entire bear range has high potential for human use (for all months of the year) with the exception of the forests above 3,000 m, the paramo habitats where the annual rainfall exceeds 800 mm, and the driest desert habitat where year-round irrigation is impossible. The former 30-m-high forest of monte cedro (Cedrela sp.), and diablo fuerte (Podocarpus sp.) of the humid forest habitat has been almost entirely replaced by fields of tea, coffee, corn, hot pepper, coca, potatoes, and oca. In the thorn forest habitat, bears find seclusion from humans and their activities in the steep terrain. The moderate slopes of up to 25" are used for grazing, growing corn, or are deforested to provide wood for fuel and the construction of lemon crates and buildings. These human activities have made the seasonally im- portant bear foods (Capparis spp., Cereus sp., Cordia rotundifolia) of the scrub desert unavailable to bears that live in the thorn forest above the human occupied zone. Spectacled bear habitat is also being reduced by the burning of grasslands and forests at the end of the dry season to create new pastures.

ACKNOWLEDGMENTS I express my gratitude to the New York Zoological Society for providing partial funding for

this study and to Dr. M. Dourojeanni Ricordi, Director General de Fauna y de Flora, Dr. C. Ponce del Prado, Sub Director de Conservacion de la Fauna Silvestre, and especially Dr. A. Brack Egg, Director del Proyecto Vicuiia, for assistance and cooperation throughout the study. Special thanks go to Dr. A. W. Erickson and Dr. C. J. Jonkel for training before the study began, and to E. Muiiiz Luna, G. del Solar, R. Marin, and I. Noya de la Piedra and their families for housing me and ~roviding assistance. Lastly, many thanks to M. Leo, R. Rodriguez, E. Ortiz, J. Pennoyer, R. Olney, and S. Tilney for accompanying and helping me in the field.

LITERATURECITED

GRIMWOOD, 1969. Notes on the distri- ta., 3:345-350. bution and status of some Peruvian mam-

BRIDGES,W. L. 1948. Wild animals of the mals. Spec. Publ., Amer. Comm. Int. Wildl. world. Garden City Publ. Co., Garden City, Prot., New York Zool. Soc., 21:l-86. New York, 272 pp. ONERN. 1976. Mapa ecologico del P e h . Ofi-

CRANDALL,L. S. 1964. The management of cina Nacional de Evaluation de Recursos wild mammals in captivity. Univ. Chicago Naturales, Lima, 146 pp. Press, 769 pp. OsGoo~,W. H. 1914. Mammals of an expe-

DAVIS, D. D. 1955. Masticatory apparatus in dition across northern Peru. Zool. Ser., Field the spectacled bear, Tremarctos ornatus, F. Mus. Nat. Hist. Publ., 10:143-185. Cuvier. Fieldiana-Zool., 37:25-46. TATE,G. H. H. 1931. Random observations

ERICKSON,A. W. 1966~.Spectacled bear-sta- on habits of South American mammals. J. tus survey in South America. Ark Underway, Mamm., 12:248-256. 2nd rept., World Wildlife Fund 1965-1967, TSCHUDI,

BRACKEGG,A. 1961. El oso de anteojos. Bio- I. R.

J. J. VON.1844. Therologie. In Un-Morges, Switzerland, 206-207. tersuchungen ueber die Fauna Peruana. St.

. 1966b. Preliminary report of investi- Gallen, 262 pp. gations on the status of the Andean specta- WALKER,E. P., ET AL. 1964. Mammals of the cled bear (Tremarctos ornatus). Unpubl. world. Johns Hopkins Press, Baltimore, prog. rept., World Wildlife Fund Proj. 187, 2:647-1500. 17 PP. New York Zoological Society, New York Zoological Park, 185th Street and Southern Blud.,

Bronx, NY 10460. Submitted 21 March 1978. Accepted 5 February 1980.

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Ecology, Distribution, and Food Habits of Spectacled Bears, Tremarctos ornatus, in PeruBernard PeytonJournal of Mammalogy, Vol. 61, No. 4. (Nov., 1980), pp. 639-652.Stable URL:

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Literarure Cited

Random Observations on Habits of South American MammalsG. H. H. TateJournal of Mammalogy, Vol. 12, No. 3. (Aug., 1931), pp. 248-256.Stable URL:

http://links.jstor.org/sici?sici=0022-2372%28193108%2912%3A3%3C248%3AROOHOS%3E2.0.CO%3B2-Q

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