One of the focus questions for our team is: How do Weddell Seal pups stay warm?
Baby Weddell Seal playing in the snow
The photo was taken under ACA Permit number 2018-013 M#1 MMPA Permit Number 21006-01
When the pups are born they have a layer of babyfur, called lanugo, but they have almost no blubber. They are usually born starting the second week of October, when the average temperature is around -19° Celsius (-2.2 ° Fahrenheit) and the average wind speed is 11 MPH. However, the conditions can be much colder and wind speed can get much higher. You can see live camera feed of McMurdo Station Weather
The research team is studying how the pups’ insulation changes over time. We will be recording when the pups molt (shed) their lanugo and we will be measuring the increase of blubber thickness over time. We will also be looking at their body composition, which is the proportion of lipid mass (blubber) vs. lean mass (muscle).
So how do we measure blubber thickness? It is with technology you most likely have heard of before, an ultrasound machine. Yes, the same machine people use to look at babies in the womb and also to visualize organs or check for tumors in adult bodies.
The ultrasound machine we use in the field
When a Weddell seal is full-grown this layer of blubber will be around 2 inches thick, which weighs about 528 pounds (240 kilograms). This means if as an adult a seal weighs 1320 pounds, 40% of its mass will be lipid (blubber).
The picture below shows an image taken from an ultrasound of one of the Weddell seal babies at a week old. The blubber layer is already 2.16 cm thick!
Ultrasound of baby Weddell seal blubber
The photo was taken under ACA Permit number 2018-013 M#1 MMPA Permit Number 21006-01
Did you know? Weddell Seal pups actually shiver to help stay warm!
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