• Email Us: [email protected]
  • Contact Us: +1 718 874 1545
  • Skip to main content
  • Skip to primary sidebar

Medical Market Report

  • Home
  • All Reports
  • About Us
  • Contact Us

We’ve Learned Why Giraffes Stick Their Necks Out – And It’s Not For Sex

June 4, 2024 by Deborah Bloomfield

The reason for giraffes’ iconic long necks has been revealed, and it turns out food was the original driver after all, just as Darwin thought. However, the alternative explanation, that it was about male sexual competition, gets a compensatory prize, having modified the shape of male giraffes’ necks.

Advertisement

Giraffes’ remarkable necks are not only their most notable feature, they’re among the most distinctive features in the entire animal kingdom. Sauropods once possessed something similar, but today there is just nothing else like that gap between head and body. Naturally, it’s something biologists are keen to explain.

Advertisement

Unfortunately, when a species’ trait serves multiple purposes, it can be hard to work out which provided the initial impetus. Darwin speculated that giraffes developed their long necks to access tree leaves no other species could. In a classic demonstration of how natural selection worked he, inspired by observations of giant tortoises, thought the proto-giraffe with the longest neck could reach more leaves than others, and became more likely to survive and pass on traits.

However, there is an alternative explanation, known as the necks-for-sex hypothesis. Not an offer from a hot but transactional vampire, necks-for-sex proposes that male giraffes developed long necks as weapons. In some species where one sex evolves a characteristic for evolutionary purposes, the other inherits it too, although usually to a lesser extent, because it’s simply easier to have more commonality. Steven Jay Gould proposed this as an explanation for the old question of why men have nipples. More recently, we have seen that the enormous noses male proboscis monkeys developed to woo mates have partially transferred to their female offspring.

Since transfer between sexes is seldom absolute, Professor Doug Cavener of Penn State University and colleagues realized that comparisons between male and female giraffes could probably settle the question. “The necks-for-sex hypothesis predicted that males would have longer necks than females,” Cavener said in a statement.

Male giraffes are 30 percent larger than females, making everything bigger, neck included. However, the team used publicly available photos of Masai giraffes (Giraffa tippelskirchi) in captivity and the wild to measure males’ and females’ relative dimensions.

Advertisement

Using the pedigree, and therefore ages, of captive giraffes the team were able to establish that at birth giraffe proportions are not affected by sex. Males grow faster, but it’s only around sexual maturity that significant differences can be seen.

Careful observations revealed that, relative to overall body size, female giraffes have longer necks, making the necks-for-sex hypothesis very unlikely. Instead, the team think it was the need for food of females that are almost constantly pregnant or nursing once they achieve sexual maturity, which drove the extraordinary neck extension. “Giraffes are picky eaters – they eat the leaves of only a few tree species, and longer necks allow them to reach deeper into the trees to get the leaves no one else can,” Cavener said.

Males do have wider necks than females, and the team think this represents an advantage when they slam their necks against those of rivals. Future research will test the suspicion that males with wider necks father more offspring. Males also have longer forelegs.

Besides the neck to body ratio, the study also revealed some other differences in male and female giraffe body shape.

Besides the neck-to-body ratio, the study also revealed some other differences in male and female giraffe body shape.

The team noticed an intriguing difference between wild and captive giraffes. The wild giraffes displayed a fairly strict sexual binary, but among captive male giraffes, 15 percent were observed to have dimensions that don’t match the typical male body plan. “We speculate that body proportion sexual dimorphisms are maintained in the wild by natural and/or sexual selection, but in captivity selection is relaxed resulting in a higher occurrence of discordances in sexual phenotypes,” the authors write. No need for a thicker neck when zookeepers play matchmaker for you. 

Advertisement

The work is not merely a way of settling long-standing debates, it could be crucial to the animals’ survival. Last year, Cavener showed Masai giraffes are more endangered than previously realized. Poaching is part of that, but habitat loss is probably a bigger factor. “If female foraging is driving this iconic trait as we suspect, it really highlights the importance of conserving their dwindling habitat,” Cavener said.

The study is open access in Mammalian Biology.

Deborah Bloomfield
Deborah Bloomfield

Related posts:

  1. Cricket-NZ players reach Dubai after ‘specific, credible threat’ derailed Pakistan tour
  2. Soccer-Liverpool’s Alexander-Arnold ruled out of Man City game
  3. What Are Baby Platypuses Called?
  4. Should You Wash Chicken Before Cooking It?

Source Link: We’ve Learned Why Giraffes Stick Their Necks Out – And It’s Not For Sex

Filed Under: News

Primary Sidebar

  • Project Hail Mary Trailer First Look: What Would Happen If The Sun Got Darker?
  • Newly Discovered Cell Structure Might Hold Key To Understanding Devastating Genetic Disorders
  • What Is Kakeya’s Needle Problem, And Why Do We Want To Solve It?
  • “I Wasn’t Prepared For The Sheer Number Of Them”: Cave Of Mummified Never-Before-Seen Eyeless Invertebrates Amazes Scientists
  • Asteroid Day At 10: How The World Is More Prepared Than Ever To Face Celestial Threats
  • What Happened When A New Zealand Man Fell Butt-First Onto A Powerful Air Hose
  • Ancient DNA Confirms Women’s Unexpected Status In One Of The Oldest Known Neolithic Settlements
  • Earth’s Weather Satellites Catch Cloud Changes… On Venus
  • Scientists Find Common Factors In People Who Have “Out-Of-Body” Experiences
  • Shocking Photos Reveal Extent Of Overfishing’s Impact On “Shrinking” Cod
  • Direct Fusion Drive Could Take Us To Sedna During Its Closest Approach In 11,000 Years
  • Earth’s Energy Imbalance Is More Than Double What It Should Be – And We Don’t Know Why
  • We May Have Misjudged A Fundamental Fact About The Cambrian Explosion
  • The Shoebill Is A Bird So Bizarre That Some People Don’t Even Believe It’s Real
  • Colossal’s “Dire Wolves” Are Now 6 Months Old – And They’ve Doubled In Size
  • How To Fake A Fossil: Find Out More In Issue 36 Of CURIOUS – Out Now
  • Is It True Earth Used To Take 420 Days To Orbit The Sun?
  • One Of The Ocean’s “Most Valuable Habitats” Grows The Only Flowers Known To Bloom In Seawater
  • World’s Largest Digital Camera Snaps 2,104 New Asteroids In 10 Hours, Mice With 2 Dads Father Their Own Offspring, And Much More This Week
  • Simplest Explanation For “Anomalous” Signals Coming From Underneath Antarctica Ruled Out
  • Business
  • Health
  • News
  • Science
  • Technology
  • +1 718 874 1545
  • +91 78878 22626
  • [email protected]
Office Address
Prudour Pvt. Ltd. 420 Lexington Avenue Suite 300 New York City, NY 10170.

Powered by Prudour Network

Copyrights © 2025 · Medical Market Report. All Rights Reserved.

Go to mobile version