This journal is brought to you by…

    Michelle with your flags
    Dr. Michelle with three of you flags. Photo credit: Alex Eilers

    • Ms. Stephanie Porter’s 2nd, 3rd, 4th, and 5th graders at Lake Cormorant Elementary
    • Ms. Karen Davis’s 5th grade class at Eastwood Elementary
    • Mrs. Barsh’s 4th grade class at Oak Elementary

    Do things in your world ever make you feel small?

    Hanging out with the Weddell seals in Antarctica sure makes me feel small!

    Just look at how big this seal is!

    How do I measure up?
    What do you think? How do I measure up? Photo credit: Dr. Jennifer Burns, MMPA Permit # 17411

    When I snuggled up next to this seal to take a photo, I realized just how small I was compared to the Weddell seal. What is one thing that makes the Weddell seal so much bigger than you or I? Any guesses?

    Large Weddell seal
    Take a look at the size of this Weddell seal. Photo credit: Alex Eilers, MMPA Permit # 17411

    If you said blubber, you are correct.

    Blubber is a special layer of fat. And with these Antarctic seals the phrase ‘bigger is better’ rings true!

    Why do you think it is good for a Weddell Seal to have so much blubber?

    Weddell seal’s weight

    A little math never hurt anybody! Get out your calculators so we can compare ourselves to the Weddell seal.

    Kids typically weigh somewhere between 50 – 150 pounds, depending on their age.

    A Weddell seal usually weighs anywhere from 500 – 1,150 pounds!

    Let’s say you weigh 100 pounds and a seal weighs 1000 pounds.

    Comparison of weights
    Compare the weight of a Weddell seal with the weight of a child.

    That seal would weigh 10 times as much as you! But how much of that is blubber?

    Blubber makes up about 20 – 40% of the Weddell seal’s body. Seals generally have a lot more body fat than us! Can you hypothesize a reason the Weddell seal might have so much more fat?

    Weddell seal shape up

    While I was out looking for seals, I noticed these seal shapes in the snow.

    Seal Angel
    This is what we call a ‘seal angel.’ Can you see where the seal was? Photo credit: Alex Eilers

    Does this looks like the outline of a seal? It should, because a seal was just resting here and left its imprint on the ice. Do you know how or why the ice melted? The seal’s body heat did that! And, how do you think the seal keeps so warm? Blubber! Blubber is an internal insulator; protecting their bodies from the cold and helping seals maintain their internal body temperature around 100° F. That’s pretty close to our body temperature, which averages around 98.6° F.

    Little Red
    A seal the team worked with last season. This one was named ‘Little Red’ and was very skinny! Photo credit: Amy Kirkham, MMPA Permit # 17411

    Another seal the team worked with last season. This one was named ‘Jupiter’ because she was so round. Photo credit: Amy Kirkham, MMPA Permit # 17411

    Why are some seals smaller than others?

    In the Antarctic summer, seals are mating, pupping, and molting. Do you think seals have more blubber or less blubber during this time of year? Well, some of the seals we examine in the summer are nice and fat, but others are much smaller. The skinnier seals we’ve worked with are moms that have been feeding their pups. These moms lose about 30% of their body mass while they produce the milk to feed their growing pups, essentially transferring their blubber to the pups. While nursing, moms also spend less time foraging for food. After they finish nursing, the new moms will have to go on several foraging trips to build up that blubber layer again. Surprisingly, these new moms can gain up to one kilogram per day and can gain about 212 pounds in only two months!

    The fatter seals are usually the skip breeders. They haven’t pupped, so they haven’t had to use their blubber reserve. Weddell seals that have lots of energy stored, like skip breeders during the summer, can have 2 inches of blubber under their skin. That thick layer can add up to 240 kilograms or 528 pounds of pure blubber!

    Weddell seal blubber
    Two inches of frozen Weddell seal blubber. Photo credit: Michelle Shero, UAA, MMPA Permit # 17411

    What’s blubber good for?

    It’s nice to keep warm, but do you think blubber might have another purpose? Blubber is a form of fat. Seals breakdown this fat when they are doing activities like molting, pupping and mating. What do all these activities have in common? They require lots of energy! Blubber is a good way to store lots of fat that the seal can break down for ENERGY. Females, especially, use a lot of energy during the pupping season to care for their pups. Most of the energy they use goes to producing their calorie-rich milk which is made of 54% fat! Mom seals get all that fat they put in their milk from their blubber.

    Pups are not born with much blubber. They have to quickly make their own, using fats from the milk that they get from their mom. The moms lose about 100 kilograms or 220 pounds of their own blubber while nursing their pups. That’s about 5 pounds of blubber per day. Wow!

    Blubber purpose

    Blubber is really neat stuff and serves two main purposes:
    * It keeps the seal warm.
    * It serves as a great way to store energy in the form of fat.

    Blubber samples

    Our research team is very interested in blubber, and we’ve been taking a lot of blubber samples!

    What else do you think we can learn from the blubber?

    Blubber sample
    A small blubber sample taken while in the field. Photo credit: Alex Eilers, MMPA Permit # 17411

    Have you ever heard the expression ‘you are what you eat?’ That expression holds true for Weddell seals, too. The Weddell’s blubber is made up of the fats that they eat. By analyzing their blubber, we can learn more about what the seals are eating. One of the big questions our research team is asking is which fish do Weddell seals eat more: Antarctic cod or Antarctic silverfish? These two fish differ in the fats they have, and so seals eating more of one species should have different fats in their blubber. Hopefully, these blubber samples can give us some clues!

    Blubber thickness

    Not only are we taking blubber samples, but we are also measuring blubber thickness. We measure the blubber thickness using an ultrasound machine.

    Using the ultrasound machine
    Using the ultrasound machine to measure blubber thickness. Photo credit: Alex Eilers, MMPA Permit # 17411

    When we put the ultrasound probe against the fur of the seal, the ultrasound machine shows us the skin layer (below, right) and the fascia, which is the part where the blubber layer and the muscle layer meet.

    Reading an ultrasound
    Reading an ultrasound screen. Photo credit: Dr. Jennifer Burns, MMPA Permit # 17411

    By measuring the distance from the skin to that layer, we can figure out how deep the blubber is (red dotted line and arrow). The team will then compare the blubber measurements gather in the November/December season to the January/February season to see if or how they have changed.

    But there is one thing about blubber that doesn’t seem to add up: why are some Weddell seals skipping their breeding cycle? These seals are nice and fat, so it is not a lack of energy!

    We are hoping to get to the bottom of some of these questions during this field season. But, as is usual with science, sometimes those answers can lead to more questions. But that is what makes scientific research so exciting!



    Alex Eilers

    Hello LCES spotlight!
    Thank you for your awesome questions!!! Sorry for the delay but here are the answers.

    Are males and females different in appearance?
    It can be a little difficult to tell the difference between male and female seals - especially for a newcomer like me. When seals are hauled out they are often resting on their bellies and you need to be able to see this region in order to tell. If the seal happens to be on its side (so their belly is visible) male seal have one small indention in their umbilical cord (belly button) region, while females have two.

    Does one sex in particular tend to be more social?
    From what I have observed , Weddell seals are fairly solitary or independent animals (although they are often seen hauled out in 'groups' or areas). Seal moms and pups appear to be the most social - as we often hear moms and pups calling to one another during the first six weeks of the pups life. After that the pups are on their own.
    Do seals choose different mates or keep the same mate for life?
    Unlike most penguin species that mate for life, Weddell seals choose different mates.

    All the best!

    Ms. Alex


    colt p

    Really good journal! I had a couple questions.My first question is what the process for analyzing seal blubber and how long does it take to get the answers for what the seal has been eating also What's the coldest temperature you guys have faced up in alaska also How long did it take for you to take your classes that were for you to get your science degree and last one How long ago did you want to become a scientist and how strong was your thought on becoming a scientist.

    Charles M

    how cold is it under the water


    have you ever been attacked by a seal

    Alex Eilers

    Many Thanks for your question!
    The answer is NO, thank goodness!

    Weddell seals are quite docile and have no land based predators, so they are relatively easy to work with. As you could imaging, the team is very thankful for that!

    Ms. Alex

    Alex Eilers

    Very cold!
    And from what I remember, I believe the water temp is around -1.8C + or -. I've written it somewhere in a journal. If you fine it I'll send you a postcard!

    You also might be interested in this website -
    You can find the sea temperatures around the world.

    Pretty cool, Huh!

    Ms. Alex

    LCES Spotlight

    We are having so much fun reading your journals! Our students had a few questions for you this morning.
    - Are males and females different in appearance?
    - Does one sex in particular tend to be more social?
    - Do seals choose different mates or keep the same mate for life?