Post by sarus on Mar 9, 2012 20:39:26 GMT -9
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CAMERA TRAP SURPRISE — Andean Bear and Giant Anteater
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The longer we have remote cameras deployed in the forests on the eastern slope of the Andes in southern Peru, the more questions I have about what is going on in those forests. Each camera has been programmed to take 10 photos in rapid sequence as soon as it detects motion, and one of the cameras took a sequence that I find simply amazing.
The first few photos show a giant anteater walking up the trail, which is not uncommon at that camera station, 1.3 miles (2.1 kilometers) off the Interoceanic Highway at 4,176 feet (1,273 meters) elevation in primary forest. As the anteater, known in Spanish as an oso hormiguero, walked out of sight below the camera, the shine of two eyes became visible in the distance. When I first saw those eyes in the photo, I assumed that they were the eyes of another anteater. However, in fact they were the eyes of another oso, an oso andino, or Andean (spectacled) bear. This bear was walking up the trail, 9 to 16 feet (3 to 5 meters) behind the giant anteater. Both animals are partially visible in one photo, so it was not a case of the camera failing to record the correct time for the photos of the Andean bear; the two animals actually were in the same place at the same time.
Giant Anteater and Spectacled Bear
I could calculate the probability that this would happen simply by chance, but I don’t think I need to: the probability would be so small that I’m confident it’s not a coincidence. So, what was the Andean bear doing there and then?
Other than coincidence, I can think of two hypotheses to explain why the animals were together. First, there is the possibility that the Andean bear was hunting the giant anteater. However, I think this is unlikely for three reasons:
A) Based on the analysis of their feces, and the evidence they leave in the forest, Andean bears are thought to be primarily vegetarian.
B) The posture of the giant anteater was not obviously any different than in any other photos, so although it had to be aware that it was being followed, there wasn’t any visual evidence that it was alarmed by the bear.
C) Giant anteaters have strong forelimbs and claws, and I don’t think they would be easy prey for a bear.
So, if the Andean bear wasn’t hunting the giant anteater, what was going on? I think my second hypothesis is plausible; I think the Andean bear may have been following the giant anteater to benefit from the anteater’s superior ability to find and excavate colonies of social insects, such as ants. In other words, the bear may have been acting as a type of parasite, waiting for the anteater to find food that it could pilfer. I don’t have any data to test the predictions of this hypothesis, I haven’t found any records of this behavior in the scientific literature, and none of the bear biologists I’ve asked has seen this type of behavior before. For now, it’s still a mystery as to why there were two types of bears in one photo.
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Source and Credit (more photos and the whole text):
► blogs.sandiegozoo.org/2010/09/03/camera-trap-surprise/
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CAMERA TRAP SURPRISE — Andean Bear and Giant Anteater
-------------------------------------------------------------------------------------
The longer we have remote cameras deployed in the forests on the eastern slope of the Andes in southern Peru, the more questions I have about what is going on in those forests. Each camera has been programmed to take 10 photos in rapid sequence as soon as it detects motion, and one of the cameras took a sequence that I find simply amazing.
The first few photos show a giant anteater walking up the trail, which is not uncommon at that camera station, 1.3 miles (2.1 kilometers) off the Interoceanic Highway at 4,176 feet (1,273 meters) elevation in primary forest. As the anteater, known in Spanish as an oso hormiguero, walked out of sight below the camera, the shine of two eyes became visible in the distance. When I first saw those eyes in the photo, I assumed that they were the eyes of another anteater. However, in fact they were the eyes of another oso, an oso andino, or Andean (spectacled) bear. This bear was walking up the trail, 9 to 16 feet (3 to 5 meters) behind the giant anteater. Both animals are partially visible in one photo, so it was not a case of the camera failing to record the correct time for the photos of the Andean bear; the two animals actually were in the same place at the same time.
Giant Anteater and Spectacled Bear
I could calculate the probability that this would happen simply by chance, but I don’t think I need to: the probability would be so small that I’m confident it’s not a coincidence. So, what was the Andean bear doing there and then?
Other than coincidence, I can think of two hypotheses to explain why the animals were together. First, there is the possibility that the Andean bear was hunting the giant anteater. However, I think this is unlikely for three reasons:
A) Based on the analysis of their feces, and the evidence they leave in the forest, Andean bears are thought to be primarily vegetarian.
B) The posture of the giant anteater was not obviously any different than in any other photos, so although it had to be aware that it was being followed, there wasn’t any visual evidence that it was alarmed by the bear.
C) Giant anteaters have strong forelimbs and claws, and I don’t think they would be easy prey for a bear.
So, if the Andean bear wasn’t hunting the giant anteater, what was going on? I think my second hypothesis is plausible; I think the Andean bear may have been following the giant anteater to benefit from the anteater’s superior ability to find and excavate colonies of social insects, such as ants. In other words, the bear may have been acting as a type of parasite, waiting for the anteater to find food that it could pilfer. I don’t have any data to test the predictions of this hypothesis, I haven’t found any records of this behavior in the scientific literature, and none of the bear biologists I’ve asked has seen this type of behavior before. For now, it’s still a mystery as to why there were two types of bears in one photo.
------------------------------------------------------------------------------------
Source and Credit (more photos and the whole text):
► blogs.sandiegozoo.org/2010/09/03/camera-trap-surprise/
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