How Old and New World Vultures Differ

Did you know that Old World and New World Vultures are not closely related? I was very surprised to learn this when I began to work with Suli, the Draper Museum Raptor Experience’s Turkey Vulture. New World Vultures reside in North, Central, and South America. Old World Vultures can be found in Africa, Asia, and Europe.

Vultures world wide have many similarities . . .

* All vultures are are scavengers. Most feed mainly on carrion, therefore helping to clean up the environment.

* The majority (though not all Old World Vultures) have featherless faces with bald or almost bald heads and necks.

* With large wingspans, vultures across the globe can soar virtually effortlessly in search of a meal.

* All vultures have strong stomach acids. This allows them to feed on rotting meat – even from diseased animals, while killing the disease within their digestive systems.

Despite all these attributes, research shows us that the Old and New World Vultures are not genetically closely related. With their strong similarities, New and Old World Vultures are an excellent example of convergent evolution, meaning the two groups evolved separately to fill a similar ecological niche.

Despite their similarities there are physical and behavioral differences between Old and New World Vultures…

* Only New World Vultures cool themselves with urohydrosis – the act of defecating down the legs, using the liquid for evaporative cooling.

* New World Vultures do not have a voice box, so can only hiss and grunt. Our visitors sometimes hear Suli hiss when she sees something with wheels, which she finds very scary. Old World Vultures, however do have voice boxes.

Listen to New World Vulture chicks hissing in this video: https://www.youtube.com/watch?v=mc5mifbRRhI

At this link you will hear the vocal sounds and hisses of the Old World White-backed Vulture: https://www.youtube.com/watch?v=uA5yGyB_z5U&t=42s

* New World Vultures do not build nests and will lay their eggs in protected locations such as old hollow logs, caves, abandoned buildings, on the ground in a thicket, or crevices of some kind. In Suli’s case her parents thought a hay stack looked like a safe location. Old World Vultures, however, do construct some type of nest. These may be nests built of sticks and leaves and are generally located in trees or on cliffs. They may use the same nest for several years taking turns sitting on the nest while their partner finds food.

* New World Vultures have weak feet used for walking and bracing against carrion as they tear off chunks of meat. Old World Vultures have stronger, gripping feet with large talons. The difference in the feet affects the way they move. New World vultures are able to run, similar to a chicken, if they need to move aside. Old World Vultures, however, are unable to run very well and instead will hop or hop/flap for short distances when needed.

* All Old World Vultures locate their food with sight. Three varieties of New World Vultures: the Turkey Vulture, and the Greater and Lesser Yellow-headed Vultures rely heavily on their excellent sense of smell. The other New World Vultures will often take advantage of the Turkey Vulture and Yellow-headed Vulture’s sense of smell, following them as they search for food.

Vultures are found on every continent except Antarctica and Australia. Even though they are not closely related, vultures are an important part of our clean-up crew – keeping our environment a healthier place to live.

Photo credits:

Hooded Vulture by John Haslam, Attribution License, https://www.flickr.com/photos/foxypar4

The Bearded Vulture was used with permission from the Peregrine Fund’s Facebook Page, https://www.facebook.com/ThePeregrineFund/?fref=ts

White-backed Vulture nest by Dutch baby, Attribution, NonCommercial, NoDerivations  License, https://www.flickr.com/photos/godutchbaby

Lesser Yellow-headed Vulture, by Paul Green, Attribution-NonCommercial-NoDerivs License, https://www.flickr.com/photos/32454602@N00/