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July 27, 2008
Here’s a story about the difficulty of teasing apart the structural legacy of ancestry from that of adaptation, and about a fossil canid that evolved back from a “wolf” to a “fox ecomorph,” both in size and in anatomy, once it became isolated on an island (Sardinia) where only small prey was abundantly available. That link is to the short version; here’s the long version (PDF).
The coauthor, Alexandra van der Geer, is at least as interesting as her subject: a paleontologist and artist with a background in veterinary medicine and art history.
Research associate for palaeontology and geomythology at the National University of Athens, Greece. Main interests: evolution of mammals on islands, paleo-pathology and geomythology. Independent research: on the border zone between animals and human culture (present project: Animals in Indian Art).
“The border zone between animals and human culture”: that’s just where the post I’m working on now
—on the fateful meetup of Homo and Canis, each genus profoundly affecting the other’s evolution—is heading.
Who Nose?
You know that dogs’ sense of smell is exponentially better than ours, that dogs can recognize a practically infinite number of individuals’ scents much as we recognize faces, but have you seen the numbers?
- A dog’s nose has about 200 million scent receptors. Ours has 5 million. (Source)
- “If all the sensory epithelia in the average dog’s nose were laid out flat, it would cover an area of about 450 square feet. . . . If an average man’s olfactory epithelia were laid out flat, it would cover about two square feet.” (Source)
- “In the brain of the average dog, more than 12 percent of the cerebral tissue is devoted to processing olfactory information. In man, less than 1 percent of the brain is devoted to olfaction.” (Same source as preceding)
- When the dog genome was sketched out five years ago (genome entrepreneur Craig Venter sequenced his own poodle, Shadow), it became evident that (not surprisingly) “substantial numbers of canine genes are employed by the olfactory system.” (Source)
We’ll be revisiting this subject in the next few months in an article on an ingenious new use for canine olfaction—helping to save endangered wildlife—that has, in turn, saved the lives of some obsessive-compulsive dogs from the pound.
(Annie Gottlieb) |
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