SPECTACLED BEAR: CHARACTERISTICS, HABITAT, FEEDING - BIOLOGY - 2024

The spectacled bear (Tremarctos ornatus) is a placental mammal endemic to South America. Its name is due to the large white circles located around the eyes, which stand out against its dark fur. These spots can spread towards the chest, simulating a bib.

The Tremarctos ornatus is also known as the Andean bear, Jukumari, frontin bear or South American bear. It lives in the humid forests of the Andean region of Venezuela, Ecuador, Peru, Bolivia and Colombia.

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It is an animal that, despite being large, easily climbs trees and rocky mountains. The spectacled bear has diurnal habits, being less active as night approaches.

It is omnivorous, rarely feeding on animals. Their diet is made up of more than 90% vegetables. This makes it, after the panda, the second species of bear that bases its diet on a large number of plants and fruits.

Despite the importance of the spectacled bear within the fauna of the Andean páramo, this species was classified by the IUCN as vulnerable to extinction. This is due to the fragmentation of their environment and their indiscriminate hunting.

Evolution

Fossil records indicate that Tremarctinae possibly originated during the prehistoric period of the Middle Miocene, in the east central region of North America. The primitive species of the spectacled bear arrived in South America during the Great American Biotic Exchange.

The tremarctine bears twice expanded to South America. The first occurred during the early Pleistocene, a time when the existence of Arctotherium burmeister was recorded for the first time, in eastern central Argentina.

The second invasion occurred at least 6000 years ago, with the entry of Tremarctos ornatus, the only member of the Ursidae family that currently inhabits the South American continent.

Fossil records

Very few fossils of T. ornatus exist in both North and South America. There are two non-exclusive reasons that could explain this. First, T. ornatus differed from T. floridanus, a sister species, in post-Pleistocene times.

This occurred because a few primitive species of Tremarctos ornatus were isolated from populations of T. floridanus, which was found in Central America. Later, the spectacled bear colonized the Andean area of ​​South America.

Another possible cause of the fossil shortage in South America could be related to the fact that the spectacled bear's environment is not suitable for fossilization. Consequently, the bone structures have not been preserved over time.

New research

The two groups of bears, one located in North America (Arctodus) and the other in South America (Arctotherium), were previously thought to be closely related. This statement was based on the anatomy of the teeth and the skull.

Thanks to advances in techniques for conducting genetic analysis, scientists obtained new information: large bears originated independently in North and South America.

The results established that the Tremarctos ornatus is related to the extinct great bear of South America. This, like the spectacled bears, consumed large amounts of vegetables in their daily diet.

General characteristics

Extremities

Its front limbs are longer than its hind limbs. The legs are flat and large, measuring around 20 centimeters. This facilitates the upright posture that it uses to widen its field of vision and to intimidate prey.

It has five toes with long, sharp, curved claws. In addition, they are not retractable, leaving a very particular mark on the ground when walking. The strength of its claws allows it, among other things, to hunt its prey and to climb trees with great ease.

Because the spectacled bear is a plantigrade animal, when moving it fully supports the palms of its legs. This causes large footprints to be left on the ground. The footprints on its hind limbs are longer and larger than those left by its front legs.

Bone structure

Tremarctos ornatus has 13 pairs of ribs, unlike other bear species that have 14 pairs. Their ocular orbits are open at the level of the skull, closing by means of a ligament.

This animal has a time line, which is associated with the remarkable muscular development in its head. One of its characteristics at the bone level is the presence of 3 fossae on the shoulder blade (scapula).

The masseteric fossa is large and divided. This could explain the ability to chew both plants and animals.

Body

The spectacled bear has a robust body. Its tail is short, approximately three inches long. This can be hidden between fur and skin, which can make it difficult to see.

Size

This species of bear is relatively small, compared to the rest of the members of the Ursidae family. It presents sexual dimorphism, the male being significantly larger than the female.

Males could weigh between 100 and 175 kilograms, measuring no less than 150 centimeters and a maximum of two meters. On average, the female weighs 65 kilograms and they are up to 33% smaller than the males.

The spectacled bear is one of the tallest placental mammals in South America. Standing on two legs it could measure up to 2.2 meters high

Fur

It has a hard, long and rough coat. It is generally black in color, although it could vary from dark brown to reddish tones. The Tremarctos ornatus is distinguished by the spots in white-yellowish tones, which surround the eyes. These are also found on the upper chest and on the muzzle.

Each member of this species has its own pattern of spots, which can be interpreted as a footprint that allows it to be identified from the rest.

Due to the warmth of the climate where it lives, the fur of the spectacled bear is thinner than that of the rest of the species in its family.

Face

The jaw is strong, with flat, broad molars that help it chew through tough vegetation, such as tree bark.

The face is rounded, with a wide and short muzzle. Its neck is thick and the ears are small, erect and round in shape.

The eyes are small. She has an excellent sense of hearing and smell, in contrast to her very limited vision.

Danger of extinction

Since 1982, the IUCN has listed the spectacled bear as a species vulnerable to extinction, due to the notable decline in its population.

Causes

Alteration of its natural habitat

Extensive agriculture and logging have caused the spectacled bear to lose much of its habitat. According to studies carried out, only 5% of the original environment of the Andean cloud forests maintain adequate conditions for the spectacled bear to develop in them.

The environment has also been affected by the different urban planning and roads that have been built in the areas surrounding the place inhabited by this animal.

All this results in, among other things, that natural sources of food become scarce. In this way, these bears may be forced to feed on livestock or nearby crops.

Indiscriminate hunting

The Tremarctos ornatus is hunted illegally to sell its meat, which is sold at high prices because it is considered exotic. The gallbladder is sold in some regions of Asia, where it is used for traditional medicinal purposes.

They are also captured and used as trophies, an aspect that was very popular during the 19th century in some rural regions of South America.

Due to the decrease in food in their habitat, these animals can attack livestock and raid part of the cultivated land. In response to this, the man attacks them, killing them.

Conservation actions

The International Union for Conservation of Nature (IUCN) recommends expanding protected areas, together with the control and supervision of those already established for this purpose.

In the same way, it considers it convenient to carry out constant monitoring of the threats to which the spectacled bear is exposed. For the success of the different programs, it is important to involve local residents, since in this way they will be the main watchdogs of their compliance.

Action plans

Governments at the national level, communities, and various protectionist organizations have made important commitments to the preservation of this species.

In Venezuela, since 1990, actions aimed at environmental education have been implemented, as well as the establishment of protection areas for the spectacled bear.

Organizations in Colombia, where the habitat of this species is highly affected, work together with the communities in order to protect this emblematic Andean species. The largest protected area is located between Peru and Bolivia, in the region known as Tambopata-Madidi.

In Ecuador and Peru, conservation strategies have yielded very valuable information on ecology, patterns of displacement, and the number of members of the population. These aspects contribute to the establishment of precise and forceful actions in favor of the protection of this animal.

Currently, a large part of the efforts revolve around the establishment, maintenance and interconnection between existing and newly established protected areas. An example of this is the Vicabamba - Amboró corridor, between Peru and Bolivia, and the conservation zones in the Venezuelan Andes.

As part of the results of the evaluation of these programs, specialists note that there are still unprotected areas. Likewise, they maintain that poaching continues to occur in an uncontrolled manner in these areas.

Taxonomy

• Animal Kingdom.
• Subkingdom Bilateria.
• Chordate Phylum.
• Vertebrate Subfilum.
• Tetrapoda superclass.
• Mammal class.
• Subclass Theria.
• Infraclass Eutheria.
• Order Carnivora.
• Family Ursidae.

Genus Tremarctos

Species Tremarctos ornatus (FG Cuvier, 1825)

Habitat and distribution

The spectacled bear is an endemic animal to the tropical Andes region. At present, this species belonging to the Ursidae family is the only one that lives in South America. Its distribution covers approximately 4,600 kilometers in the Andean mountains, from Venezuela to Bolivia.

From north to south, these animals are located in the Sierra de Perijá and the Andes Mountains, in Mérida - Venezuela and the eastern, central and western Andean mountain ranges of Colombia. In the equatorial Andean region, they are located towards the eastern and western slopes.

They also inhabit the 3 Andean mountain ranges of Peru, including a desert area on the North Pacific coast. In Bolivia, it is distributed on the eastern slope of the tropical Andes.

Years ago the possible presence of Tremarctos ornatus in Panama was reported. However, investigations carried out in the area did not yield any evidence that could corroborate this claim.

Currently, the existence of some members of this species in northern Argentina has been confirmed. However, because this region is located around 300 km south of Bolivia, it could be some spectacled bears that roam the place. In this way, they may not represent a resident population as such.

Altitudinal range

This species of mammal ranges from 200 to 4,750 m asl, occupying an area of ​​approximately 260,000 km² along the tropical Andes. The lower limit is in the western Peruvian range, while the upper limit is within the Carrasco National Park, in Bolivia.

Habitat

The species inhabits a great diversity of ecosystems in the tropical Andes. These include tropical humid lowlands, dry tropical forests, and montane forests.

They also tend to live in wet and dry tropical shrubs and high-altitude grasslands. However, it has not been proven that they could inhabit those moors and high grasslands that do not have access to forested regions.

In the coastal region of Peru, the Tremarctos ornatus is found in tropical dry scrub. Due to the availability of food, spectacled bears may carry out some type of seasonal migrations.

A common characteristic of the various regions where this animal lives is humidity. The dense cloud forests have annual rainfall in excess of 1,000 mm.

Feeding

Despite belonging to the carnivorous order, the Tremarctos ornatus diet is only composed of 5% meat. The vast majority of their food is fruits and plants.

Regarding the material of plant origin, the spectacled bear consumes orchid bulbs, nuts and fibers of palms, frailejón (Espeletia spp.) And cacti. He also likes the heart of bamboo, sugar cane (Saccharum ssp.) And mosses.

One of his favorite plants is the bromeliad (Puya ssp., Tillandsia ssp., And Guzmania ssp.), Of which he usually ingests the inner part, which is more tender. Fruits, which you eat seasonally, are important because they provide you with the protein, carbohydrates, and fats you need.

Sometimes the Tremarctos ornatus can descend from the humid forest and break into the corn (Zea mays) crops. They also tend to eat the bark of the tree, which they shed to ingest the second nutrient layer.

Spectacled bear prey is generally small, however it can hunt llamas, deer, horses, and domestic cattle. Rabbits, nesting birds, tapirs, mice and some arthropods are also included in their diet.

Feeding techniques

This animal is an excellent tree climber. Once on them, they often build a platform. In it they can rest, hide from a threat, eat some fruits and even use them as a store for their food.

This structure is also used to have a better reach of those foods, such as orchids, fruits and bromeliads, which are found in the canopy of the tree.

Because, among other things, food is available throughout the year, spectacled bears do not hibernate. The activity patterns of the Tremarctos ornatus are fundamentally diurnal, and can vary according to the season and between each geographical area.

This species is usually solitary, however they could form small groups to feed themselves, when they get an area with a great source of food. In a corn field, up to 9 bears could be found together, consuming this grass together.

Anatomical adaptations for a herbivorous diet

The spectacled bear is, after the panda, the second bear that consumes the most amount of vegetables in its diet. This has caused his body to have undergone some modifications, which allow him to adapt to his type of diet.

In relation to its body size, the Tremarctos ornatus has the largest mandibular zygomatic muscle and the shortest snout of almost all different species of bears, the exception being the panda bear, which slightly exceeds it in relative size.

The fourth premolar has 3 pulp cavities and 3 roots. The strong jaw muscle and its teeth allow it to grind and chew strong foods, such as tree bark.

Spectacled bears have a simple stomach, with a very muscular pylorus. The intestine is short, lacking a cecum.

Reproduction

The male of this species matures sexually between 4 and 8 years, while the female does it around 4 and 7 years. The male reproductive system is characterized by the fact that the testes increase in size during the reproductive stage and by having a small prostate gland.

Males have small glandular-like blisters at the distal ends of the vas deferens. In some lactating females, the two posterior pairs of nipples develop more than the anterior pair, which remains small.

The spectacled bear can reproduce at any time of the year, however it usually occurs between the months of March to October, a time when there is greater abundance of food.

During courtship, the couple may spend several days trying to get closer to each other. When contact is finally made with each other, the spectacled bears may nudge and bite on the neck and head. They could even go as far as fighting each other.

These courtship behaviors occur while the female is in her estrous cycle, which generally lasts between 1 and 5 days. The couple stays together for a week or two, copulating several times during that time.

Gestation and delivery

Gestation can last between 160 and 255 days, suggesting that the female spectacled bear has delayed implantation. In this, the cell division that occurs in the embryo stops and its attachment to the uterus is delayed for several months.

Thus, the female can plan the gestation and delivery period, ensuring that the calf is born around 3 months before the fruit season begins. When these are mature, the cub will have already been weaned and can eat them.

Once the female is in gestation, build a burrow. In it, she places dry plants on the ground, with the intention of making a kind of nest. One to three cubs can be born at each birth.

The calf is born weighing around 300 grams and measuring 35 centimeters, its eyes are closed and it lacks fur. After about 15 days they open their eyes. The female takes immediate care of the cub, which includes its protection and feeding with mother's milk.

Subsequently, she periodically leaves the burrow in search of food for her young. After 2 or 3 months, the cubs leave the maternal shelter and by the fourth month they can climb to take fruits and bromeliads from the trees.

Behavior

The Tremarctos ornatus is a fundamentally solitary animal. It is during mating that the female is almost exclusively with the male for a short time. Its habits are generally diurnal, although it can occasionally be active at twilight.

Although they are large animals, they are very good swimmers. The spectacled bear climbs trees to build his resting platform or to grab some fruit. As it climbs, it leaves deep scratches on the tree trunk. These marks are used to communicate, delimiting the territory it inhabits.

The Spectacled Bear is shy, they often tend to isolate themselves. In this way they avoid competition with members of their own species.

If he does meet other bears or even the human, the initial impulse is not aggressive, but he is cautious. However, feeling threatened, it attacks the enemy, as happens when a predator approaches its cubs.

Its most developed sense is smell, from the ground it can feel when the fruit of the tree is ripe. To communicate, they emit various types of vocalizations, growl when they are afraid or scream when they are fighting for food.

References

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