{"id":2000124895,"date":"2026-09-05T13:16:00","date_gmt":"2026-09-05T11:16:00","guid":{"rendered":"https:\/\/new.igihe.com\/english\/?p=2000124895"},"modified":"2026-09-05T12:10:43","modified_gmt":"2026-09-05T10:10:43","slug":"scientists-overturn-long-held-theory-about-bonnethead-sharks-unusual-heads","status":"publish","type":"post","link":"https:\/\/new.igihe.com\/english\/scientists-overturn-long-held-theory-about-bonnethead-sharks-unusual-heads\/","title":{"rendered":"Scientists overturn long-held theory about bonnethead sharks\u2019 unusual heads"},"content":{"rendered":"\n

Bonnethead sharks, scientifically known as Sphyrna tiburo, are small relatives of hammerhead sharks and are recognized by their distinctive shovel-shaped heads. <\/p>\n\n\n\n

They are the only shark species currently known to show clear differences in head shape between males and females.<\/p>\n\n\n\n

Adult male bonnethead sharks typically have a more pointed head, while females tend to have a smoother and rounder shape. <\/p>\n\n\n\n

Scientists had previously suggested that the pointed shape in males developed when they reached sexual maturity.<\/p>\n\n\n\n

However, a new study has found that the process is more complicated.<\/p>\n\n\n\n

Researchers discovered that young bonnethead sharks of both sexes initially have relatively pointed heads. <\/p>\n\n\n\n

As the sharks grow older, their heads gradually become rounder, with the change being much more pronounced in females.<\/p>\n\n\n\n

The finding challenges the idea that males develop their pointed heads as a result of reaching sexual maturity.<\/p>\n\n\n\n

The researchers also investigated whether differences in diet could explain the different head shapes.<\/p>\n\n\n\n

They studied bonnethead sharks from Biscayne Bay and Tampa Bay in Florida and found that the two populations fed within different food webs.<\/p>\n\n\n\n

However, males and females living in the same area generally relied on similar food sources.<\/p>\n\n\n\n

This suggested that differences in diet or feeding behaviour were unlikely to be responsible for the differences in head shape.<\/p>\n\n\n\n

Between May 2022 and May 2023, researchers sampled 105 bonnethead sharks in Biscayne Bay and another 39 in the Tampa Bay region.<\/p>\n\n\n\n

They measured the sharks and photographed their heads before releasing them. The researchers later analyzed the photographs to measure the curvature and shape of the sharks\u2019 heads.<\/p>\n\n\n\n

They also examined muscle samples from 137 sharks for carbon and nitrogen isotope signatures. <\/p>\n\n\n\n

These chemical markers helped researchers understand the sharks\u2019 positions within local food webs and identify differences between populations.<\/p>\n\n\n\n

Although the study ruled out diet as the main explanation, scientists still do not know exactly why the sharks\u2019 head shapes change differently between males and females.<\/p>\n\n\n\n

Researchers believe swimming performance or changes linked to reproduction could provide possible explanations. <\/p>\n\n\n\n

Future studies may examine how head shape develops during embryonic growth and whether different head shapes provide swimming advantages at different stages of life.<\/p>\n\n\n\n

The researchers also plan to study bonnethead sharks from other areas to determine whether similar patterns occur across different populations.<\/p>\n\n\n\n

\"\"
A bonnethead shark, a small relative of hammerhead sharks, known for its distinctive shovel-shaped head.<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"

Scientists have challenged a long-held explanation for why male and female bonnethead sharks develop differently shaped heads, revealing that the unusual shape changes in a surprising way as the animals grow.<\/p>\n","protected":false},"author":139,"featured_media":2000124899,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14],"tags":[],"byline":[201],"hashtag":[],"class_list":["post-2000124895","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-environment","byline-rania-umutoni"],"bylines":[{"id":201,"name":"Rania Umutoni","slug":"rania-umutoni","description":"","image":{"id":2000122457,"url":"https:\/\/cdn.igihe.com\/en\/2026\/08\/WhatsApp-Image-2026-08-14-at-12.00.00-PM.jpeg","title":"WhatsApp Image 2026-08-14 at 12.00.00 PM","mime_type":"image\/jpeg"},"user_id":139}],"contributors":[{"id":201,"name":"Rania Umutoni","slug":"rania-umutoni","description":"","image":{"id":2000122457,"url":"https:\/\/cdn.igihe.com\/en\/2026\/08\/WhatsApp-Image-2026-08-14-at-12.00.00-PM.jpeg","title":"WhatsApp Image 2026-08-14 at 12.00.00 PM","mime_type":"image\/jpeg"},"user_id":139}],"featured_image":{"id":2000124899,"url":"https:\/\/cdn.igihe.com\/en\/2026\/09\/bonnethead-shark-sandy-beach.webp","alt":"","caption":"","mime_type":"image\/webp","width":1920,"height":1080,"sizes":{"thumbnail":{"url":"https:\/\/cdn.igihe.com\/en\/2026\/09\/bonnethead-shark-sandy-beach.webp","width":1920,"height":1080},"medium":{"url":"https:\/\/cdn.igihe.com\/en\/2026\/09\/bonnethead-shark-sandy-beach.webp","width":1920,"height":1080},"medium_large":{"url":"https:\/\/cdn.igihe.com\/en\/2026\/09\/bonnethead-shark-sandy-beach.webp","width":1920,"height":1080},"large":{"url":"https:\/\/cdn.igihe.com\/en\/2026\/09\/bonnethead-shark-sandy-beach.webp","width":1920,"height":1080},"full":{"url":"https:\/\/cdn.igihe.com\/en\/2026\/09\/bonnethead-shark-sandy-beach.webp","width":1920,"height":1080}}},"_links":{"self":[{"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/posts\/2000124895","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/users\/139"}],"replies":[{"embeddable":true,"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/comments?post=2000124895"}],"version-history":[{"count":2,"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/posts\/2000124895\/revisions"}],"predecessor-version":[{"id":2000124901,"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/posts\/2000124895\/revisions\/2000124901"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/media\/2000124899"}],"wp:attachment":[{"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/media?parent=2000124895"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/categories?post=2000124895"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/tags?post=2000124895"},{"taxonomy":"byline","embeddable":true,"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/byline?post=2000124895"},{"taxonomy":"hashtag","embeddable":true,"href":"https:\/\/new.igihe.com\/english\/wp-json\/wp\/v2\/hashtag?post=2000124895"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}