Animals & Wildlife Magazine

Weddell Seals Found to Be Born with Abnormally Large Brains

By Frontiergap @FrontierGap

Weddell seals are born with brains which are 70% the size of their parents, but a body mass of only 6-7%. The reason for this precocial development of the brain, when body fat is so crucial to mammals in Antarctic conditions-developing navigation skills.

Weddell seals found to be born with abnormally large brains

Image courtesy of Chad Rosenthal

Weddell seals (Leptonychotes weddellii) will travel huge distances beneath sheets of sea ice surfacing through air holes in the ice as infrequently as every hour. They can travel up to 20km in this time and come to rest in the Antarctic sheets. The Female Weddell seal will give birth on the ice sheets, protecting the offspring from killer whales (Orcinusorca) and leopard seals (Hydrurga leptonyx) which do not travel so far under ice. Once they are born, the Weddell seal pup has a limited time with its mother to develop the brain functions and skills it will need in the water to navigate in such a dangerous environment and learn to quickly scan for air holes in the ice.  An article published in Marine mammal science recently, found that the pups are born with less body fat than other seals in a similar environment but a brain which is 70% its adult size. A human brain is only around 25% its adult size when we are born.

Seals were a good species for the focus of the study, as often marine mammals will have larger brains than terrestrial mammals of a similar size. This is put down to coping with navigation in a complex marine environment and developing communication skills-especially in social cetaceans like dolphins. The Weddell seal pups first takes to the water at only 7-12days old. At this point it will not have gained much fat from nursing from their mother as much of energy they derive from the milk is used by their brain and they will still have their lanugo (a downy fur present in the womb which is shed after a few weeks and replaced with their more protective adult coat).

On entering the icey water with little physical protection, the pups become very cold and will often be observed shivering. The early immersion into temperatures of around (-1.8c) can lead to pup mortality due to hypothermia and some will drown as they are unable to get back on to the ice through ice holes. Interestingly, the Weddell seal is not driven in to the water early by environmental pressure (such as ice melt or tide) but the need to develop spatial memory and motor skills for traveling in under ice environments. Since they will only have around 40-50 days in which to develop and learn these skills with their mother before they are left to be independent, the Weddell pup has to take the risks to get an early start. Being born with such a large brain allows the pups to make the most of the short time they have to hone these vital skills.

By Emma Gardner

Back to Featured Articles on Logo Paperblog

These articles might interest you :

  • A Daytrip to Old Port Royal

    Daytrip Port Royal

    One thing I find both terrible and embarrassing is that on a tiny island like Roatan, it has taken me YEARS to get to some of the destinations around here. Read more

    The 05 September 2015 by   Cubiclethrowdown
  • Cartoon Guide to Biodiversity Loss XXXII

    Cartoon Guide Biodiversity Loss XXXII

    Six more biodiversity cartoons — this time, from France. They’re in French to pay hommage to my hosts (and acknowledge their fanaticism for les bandes... Read more

    The 07 September 2015 by   Bradshaw
  • #bloggersforrefugees Urgent Need & Photo Diary

    #bloggersforrefugees Urgent Need Photo Diary

    The current massive influx of refugees into Europe has been a media and humanity crisis this entire summer.Everyone is expressing their own opinion on the... Read more

    The 07 September 2015 by   Shegotherown
  • Dallas Smith with Cold Creek County at the CNE 2015

    Dallas Smith with Cold Creek County 2015

    On Sunday the boys from Cold Creek County showed up to sing to us about Our Town and Beer Weather and beer weather it certainly was. Read more

    The 08 September 2015 by   Phjoshua
  • Book Excerpt: In Sheep’s Clothing – L.D. Beyer

    As the clay disk sailed out of the trap house, the President swung his gun, tracking the target. A gentle squeeze of the trigger and the target exploded, nothin... Read more

    The 05 September 2015 by   Donnambr
  • Less Than Optimal

    If you’ve tried to access this blog lately from the Optus network, I’m going to make an educated guess and say that you haven’t been able to. Read more

    The 07 September 2015 by   Betchaboy

Add a comment