Giraffes’ secret to maintaining such a long, elegant neck that keeps their heart so far away from their brain is that they have twice the blood pressure of other mammals. For the first time, scientists sequenced the complete genome of these unique African animals and found this and other clues about the evolution of their distinctive characteristics.
The paper, published Tuesday in the journal Nature Communications, reveals that giraffes have a “turbo-charged heart” that’s capable of pumping blood two meters up to the brain cells. Their neck evolved through dozens of mutations over 20 million years alongside their powerful cardiovascular system.
The tallest animal on Earth has special safety valves that allow it to bend down and effortlessly raise its head again to continue reaching delicious leaves without fainting. Aside from the blood pressure that’s twice as high as in other mammals, their turbocharged cardiovascular system is the result of a rarely large left ventricle the giraffe’s heart evolved, the paper explains.
“There are many theories about how the giraffe’s neck lengthened but it does seem that the development of the cardiovascular system evolved in parallel with the development of the skeletal system,” declared Morris Agaba of the African Institute for Science and Technology in Tanzania, as reported by Reuters.
Lead author Professor Douglas Cavener, from Penn State University, told MailOnline that a few well-known regulatory genes are probably linked to the giraffe’s distinctive stature and powerful cardiovascular system. The research team identified 70 genes that are responsible for the animal’s adaptation compared to other mammals.
Another interesting characteristic the study includes is giraffe’s sprints, which can reach 60 kilometers per hour (37 mph).
Similarities with humans and other mammals
In spite of the giraffe’s unique features, this majestic animal has on its neck and legs the same number of bones as those found in all mammals, unlike long-necked birds with additional vertebrae. Giraffes have the same seven cervical vertebrae as humans, although theirs are up to 25 or 28 cm long (10 or 11 inches).
Giraffes have something in common with okapis, too
Researchers were able to discover interesting facts about giraffes by comparing their genome with the short-necked okapi. This animal happens to be giraffe’s closest relative, since they derived from the same ancestor about 12 million years ago, Professor Cavener informed.
The okapi looks more like a zebra and it doesn’t have the giraffe’s height nor its remarkable cardiovascular capabilities, but it helped scientists find out about the changes in a few genes responsible for regulating circulation and body shape in giraffes.
The scopes of the study
Discovering the genetic factors linked to the cardiovascular system of the giraffe could help experts in human health find new methods to treat people with high blood pressure, given that this fantastic animal seems to avoid organ damage in spite of having twice the blood pressure as other mammals.
Professor Cavender told MailOnline that the research team will conduct experimental tests to identify candidate genes to confirm whether they are behind the giraffe’s distinctive features. Dr. Agaba added that, in order to clear the way to apply the findings to human and animal health, scientists will collect experimental data to validate the identified genes’ functions and then accurately detect the genetic mechanisms involved.
Source: Daily Mail