Friday, April 6, 2012

Turkey Vultures Have Super-Sniffers

Vulture12 (2)
© Joshin Yamada (via Wikimedia Commons)
Take a close look at this vulture's nostrils. Notice that you can see clear through to the green grass outside the window! This is because the turkey vulture doesn't have a nasal septum (the wall that separates the nostrils). The turkey vulture shares this quality with the other two North American vulture species -- the California condor and black vulture. The turkey vulture's nostrils are the largest of the three species, making the see-through aspect much more noticeable. It's easy for the bird to keep these big open nostrils clean, which is important when you often have to stick your head inside carcasses to eat. One of the last things a turkey vulture needs is a sinus infection brought on by bits of partially rotten meat getting stuck inside his "nose." The perforated nostrils also allow more air to pass through, and with that air, come the molecules that make smells.

There's more to the turkey vulture's amazing sense of smell than just large nostrils. Most of our feathered friends have larger optic lobes in their brains, which process vision, and smaller olfactory bulbs, which process scents. This means that your average bird can't smell very well. Of course, there are exceptions, and the turkey vulture is one of the big exceptions. Put the enlarged olfactory bulb together with the nostrils, and they add up to make one highly developed sense of smell. There's still quite a bit of debate about exactly how powerful that sniffer is. All ornithologists agree that turkey vultures can follow their noses to locate food when the birds are walking on the ground or soaring just above the tree tops. However, some researchers say that it's unlikely that these vultures can smell food from higher soaring altitudes.

Bonus fact: Turkey vultures have been used to locate gas leaks. The compound added to the gas as a warning signal (what makes it stinky) is ethyl mercaptan, which is one of the gasses given off by rotting carrion.

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