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


You Might Also Like :

Back to Featured Articles on Logo Paperblog

These articles might interest you :

  • Why You Should Care: Trump’s Order on the Border Wall

    Should Care: Trump’s Order Border Wall

    GR: In the midst of the greatest mass extinction in Earth history, the U. S. government is stepping in to do even more to disrupt wildlife movements and put mor... Read more

    By  Garry Rogers
    ANIMALS & WILDLIFE, ENVIRONMENT
  • Koalas Are Fading Away

    Koalas Fading Away

    GR: I would add that not only are habitat losses causing greater short-term harm than climate change, so are invasive species. Read more

    By  Garry Rogers
    ANIMALS & WILDLIFE, BOOKS, ENVIRONMENT
  • Ants Behave as Mini Farmers in Fiji

    Ants Behave Mini Farmers Fiji

    GR: We just discovered something about ants that has gone on for millions of years. “Ants found in the Pacific islands of Fiji behave as miniature farmers,... Read more

    By  Garry Rogers
    ANIMALS & WILDLIFE, ENVIRONMENT
  • Maps Reveal How Global Consumption Hurts Wildlife

    Maps Reveal Global Consumption Hurts Wildlife

    Map shows species-threat hot spots linked to consumption in the United States. The scale bars indicate the total of all the fractions of threats to land or... Read more

    By  Garry Rogers
    ANIMALS & WILDLIFE, ENVIRONMENT
  • Platform Addition for the Justice Democrats

    Platform Addition Justice Democrats

    Justice Democrats Platform Omission Monarch butterfly at Coldwater Farm. I agree with the 20 items included in the Justice Democrats platform. My concerns for... Read more

    By  Garry Rogers
    ANIMALS & WILDLIFE, ENVIRONMENT
  • The Conservation Status Of Christmas Wildlife

    Conservation Status Christmas Wildlife

    Colder weather is no problem for well adapted winter species around Christmas time, but what threatens the species that we usually associate with the festive... Read more

    By  Frontiergap
    ANIMALS & WILDLIFE, ENVIRONMENT
  • Ayurvedic Treatment of Friedreich’s Ataxia

    Ayurvedic Treatment Friedreich’s Ataxia

    Friedreich’s ataxia is a rare hereditary degenerative disease that mainly affects the nervous system and the heart. Also known as spine cerebellar degeneration... Read more

    By  Dr Vikram Chauhan
    HEALTH