By Dr. Becker
Vultures, with their bald heads, beady eyes and penchant for rotting meat, are among the most reviled of birds. Even Charles Darwin is said to have called them “disgusting birds.”1
But the general negativity directed toward vultures is highly misguided and has contributed to a poor reputation that must be changed, in my opinion. As one of my most favorite species of birds, these amazing creatures fulfill a critical ecologic role, and many populations are in peril.
The birds serve as the garbage collectors of nature, an incredibly important job that may only be fully appreciated once it stops.
And this is a very real possibility, as vulture populations are on the decline. In reality, vultures are magnificent and fascinating birds that researchers are only beginning to fully understand.
How Do Vultures Eat Rotting Meat Without Getting Sick?
Researchers have succeeded in sequencing the genome of a Eurasian (Old World or cinereous) vulture, a first for science.2
The vulture genome was then compared to that of a bald eagle. In so doing, researchers were able to pinpoint some key vulture secrets, including how they can thrive in the face of constant exposure to pathogens.
As has been suspected, vultures are genetically suited to a scavenging lifestyle. They have variations in genes that regulate the secretion of gastric acid, which may help them to digest carcasses.
They also have other notable genetic variations, including in genes associated with immunity and defense against microbial and viral infections. According to Science Daily:3
“These included genes that allow cells to take up microorganisms and target pathogens for ingestion and elimination. The authors suggest that these may play a role in helping the vulture species combat pathogens encountered in their diet and complement the role of gastric secretion.”
Old World Vultures Are Somewhere “Between a Vulture and an Eagle”
Interestingly, the Old World vulture species, which live in Africa, Asia and Europe, is thought to have diverged from the North American bald eagle a relatively recent 18 million years ago. The birds are more closely related to bald eagles than to New World vultures, which are found in the Americas.
Genetically speaking, the researchers said the Old World vultures are a cross between a vulture and an eagle, and by understanding their genetic makeup it could even lead to advances in human health.
Lead author Jong Bhak from Ulsan National Institute of Science and Technology, South Korea, told Science Daily:4
“This is the first Old World vulture genome that has been reported, and we can see that the cinereous vulture has genetic signatures for resisting infection from eating decaying flesh.
Understanding the genetic make-up of extreme life forms has potential for improving human health. The immune system genes we've identified could be useful targets in humans for protection against infection."
Why Vultures Deserve More Respect
Despite their appearance, or perhaps because of it, vultures are charismatic creatures. They’re also social and intelligent. They will drop eggs onto rocks to crack them open or even throw stones at ostrich eggs to break them apart.5
Some vultures are known to mate for life and when an egg is laid (vultures lay only one egg per year or two), both males and females incubate it and feed the hatched chick. Vultures may live in colonies of up to 1,000 mating pairs, and they also feed in large groups.6
They have some impressive skills too, like being able to spot a carcass 20 miles away.7 And while most birds can’t smell, turkey vultures can and are capable of smelling rotten meat from more than a mile away.8 Perhaps most astonishing of all is their work to clean up nature. As written by National Geographic:9
“ … they perform a crucial but massively underrated ecosystem service: the rapid cleanup, and recycling, of dead animals.
By one estimate, vultures either residing in or commuting into the Serengeti ecosystem during the annual migration — when 1.3 million white-bearded wildebeests shuffle between Kenya and Tanzania — historically consumed more meat than all mammalian carnivores in the Serengeti combined.
And they do it fast. A vulture can wolf more than two pounds of meat in a minute; a sizable crowd can strip a zebra — nose to tail — in 30 minutes.
Without vultures, reeking carcasses would likely linger longer, insect populations would boom, and diseases would spread — to people, livestock, and other wild animals.”
Vultures Are at Risk From Poisoning and Poachers
Vultures, which are heavily targeted by poachers and poisoning, are facing a growing risk of extinction. Six vulture species in Africa have been moved to more critical categories on IUCN’s Red List.10
There, ivory poachers may sprinkle dead elephants with poison, such as Furadan, because their presence in the sky alerts game wardens to their illegal activities.
If a lion kills a farmer’s livestock, meanwhile, he may retaliate by sprinkling its carcass with poison, which kills the lions and the vultures that come back to feed. In Africa, populations of eight vulture species declined by an average of 62 percent, and seven had declined at a rate of 80 percent or more, over three generations, according to a study published in Conservation Letters.11
Several species of vulture on the Indian subcontinent are also in extreme danger of extinction due to cattle contaminated with the painkiller diclofenac. National Geographic reported:12
“In India populations of the most common vultures — white-rumped, long-billed, and slender-billed — declined by more than 96 percent in just a single decade.
Then in 2003 researchers from the Peregrine Fund definitively linked bird carcasses with cattle that had been treated with an anti-inflammatory called diclofenac.
Initially prescribed for arthritis and other pain in humans, the drug had been approved for veterinary use in 1993. In vultures, diclofenac causes kidney failure: Autopsies reveal organs coated with white crystals.”
The Indian government has taken major strides to help save vultures by banning veterinary diclofenac although similar drugs are still being used. In Africa, vulture populations continue to decline both due to poisoning and poaching; in the region, vulture brains are believed to offer the ability to see into the future.