More on Spectacled Bears (Tremarctos ornatus)

Spectacled Bear

Wild Spectacled Bear unconcerned by my presence.
Photo: Lou Jost/EcoMinga

I’ve only seen wild Spectacled Bears twice. The first time, the bear literally fell out of a tree from fright when it saw me! The second time, several years later, the bear paid no attention at all, and I was able to approach closely and take as many photos as I wanted. Above and at the end of this post are a couple of those pictures.

Our reserve caretakers have seen bears a few times in our reserves, especially Cerro Candelaria Reserve and our new adjacent Naturetrek Reserve. Once, our caretaker Luis Recalde found a bear in the Naturetrek Reserve, but realized he had left his camera at home, an hour’s walk from the spot. He ran home, then went back up the mountain with his camera, and the bear was still there, eating Clusia fruits! These are some of his pictures from that day:

Spectacled Bear

Spectacled Bear in our Naturetrek Reserve, in the rain. Photo: Luis Recalde/EcoMinga.

Spectacled Bear

Spectacled Bear in our Naturetrek Reserve. Photo: Luis Recalde/EcoMinga.

Spectacled Bear

Spectacled Bear. Photo: Luis Recalde/EcoMinga.

The Spectacled Bear looks a lot like the medium-sized temperate-zone Black Bear (Ursus americanus), except for its distinctive tan or whitish “eyeglasses” (which are often incomplete). However, DNA and morphological analysis reveals that this resemblance is only superficial, and that the Spectacled Bear is not closely related to any of the world’s other living bear species. One clue to this is their number of chromosomes: 52 pair instead of the 74 pair found in all other living bears except the panda (which has 42 chromosomes). Bears first appear in the fossil record around 30 million years ago; these were more like badgers than like today’s bears. They probably evolved in Eurasia but soon spread to North America. Around 20 million years ago in Asia, an offshoot of the main bear lineage led to today’s pandas. Then around ten to thirteen million years ago in North America, another offshoot of the main bear lineage appeared. This offshoot is called the Tremarctinae, and it led to our Spectacled Bear. All the other living bears diverged from each other relatively recently, less than six million years ago.

The Tremarctinae offshoot that eventually produced the Spectacled Bear also produced perhaps the largest carnivorous land mammals that ever lived, the Short-faced Bears (Arctodus and Arctotherium). These things weighed more than a ton! The earliest fossils of Short-faced Bears date from about 4 to 5 million years ago, contemporary with an extinct species of Spectacled Bear (Tremarctos floridanus) in North America. The Short-faced Bears evolved specialized carnivore features, while the extinct species of Spectacled Bear evolved specialized herbivore features. Because of these differences in feeding habits there was some uncertainty about whether the Short-faced Bears were really related to the Spectacled Bears. In 2008 it became possible to extract DNA from ancient Short-faced Bear remains, and this DNA confirmed that they were the closest relatives of the Spectacled Bears.

Arctodus

Arctodus. Photo: Wikipedia Commons

Both these bear genera spread into South America when that continent was joined to North America by the rising Isthmus of Panama around 2-3 million years ago. Lucky for us tropical biologists, both the North and South American Short-faced Bears became extinct about 10000 years ago. The North American Spectacled Bear also became extinct around that time. The only survivor of this extraordinary group of bears is our Spectacled Bear (Tremarctos ornatus).

Male Spectacled Bears can reach 200 kg but females only reach a quarter of that weight. They eat mostly fruits and berries, bromeliad hearts, and palm hearts, but occasionally they manage to kill and eat young Mountain Tapir or other animals, including (rarely) cattle. The local people here are afraid of them, but actual reports of attacks on humans are very rare. One recent death in Peru was reported, but it was due to a bear falling out of a tree and killing the hunter who shot it!

Spectacled Bears are found in the Andes and foothills of Colombia, Venezuela, Ecuador, Peru, and Bolivia, with some populations spreading to low elevations, especially in the dry forests of Peru. There may possibly be some in the Darien of Panama and in northern Argentina. The total population is estimated to be at least 20000 individuals and possibly several times that, but population is hard to estimate and hunting can eliminate them from areas which appear suitable. People hunt them because they eat crops (especially corn), or for meat and fat, or for special body parts which are used in local traditional medicines and exported for oriental medicine.

Males have home ranges perhaps around 60 sq km while females have ranges of about 15 sq km. However, ranges of individual females can overlap. That means our Cerro Candelaria Reserve, by itself, could support perhaps one male and two to four females. This is not enough for a sustainable population, but the highest-elevation parts of our reserve adjoin the very large Sangay National Park, so our population is likely to remain stable. Bears move up and down slopes seasonally, so our protected low-elevation habitat may also be very important for the survival of the bears in the northern section of Sangay National Park (which contains mostly high-elevation habitats). Eventually we hope to create a protected biological corridor between Sangay National Park and the Llanganates National Park, to help ensure sustainability of the large mammal populations in both parks and in our own reserves. This area has been declared an Ecological Corridor by the relevant municipalities, and has been declared a “Gift to the Earth” by WWF, but nothing real has been done to protect the area. Our reserves do offer real protection.

Lou Jost
http://www.ecominga.com
http://www.loujost.com

Spectacled Bear

Spectacled Bear in its temporary sleeping nest. Photo: Lou Jost/EcoMinga

Note to geneticists: The divergence times I gave above are from analyses of molecular data by Yu et al 2007 and Krause et al 2008 based on mitochondrial DNA, which often underestimate divergence times. For a discussion of the dangers of using of mitochondrial DNA for bear dating, see Jerry Coyne’s website post: http://whyevolutionistrue.wordpress.com/2012/07/24/a-new-study-of-polar-bears-underlines-the-dangers-of-reconstructing-evolution-from-mitochondrial-dna/

Online resources:

Yu et al (2007). Analysis of complete mitochondrial genome sequences increases phylogenetic resolution of bears (Ursidae), a mammalian family that experienced rapid speciation.

Krause et al (2008).Mitochondrial genomes reveal an explosive radiation of extinct and extant bears near the Miocene-Pliocene boundary.

Anne-Marie Hodge. Updated Range of Immensity for Arctotherium: New Record for Largest Known Bear

9 thoughts on “More on Spectacled Bears (Tremarctos ornatus)

  1. Spectacled Bear is spectacular!
    Lou and Luis were lucky to meet a Spectacled Bear.
    Thanks for sharing your remarkable photos and experiences.

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