Terrie Williams using ultrasound on Seal 29

Dear Friend,

Scientist Terrie Williams wants to know how seals keep warm in the Antarctic. She starts by asking, “How thick is the seal’s fat layer?” She finds and records the answer with the help of an ultrasound machine. It uses painless high-frequency sound waves and their echoes to make pictures of the tissues under the skin. Williams also wants to know how much blubber it takes for seals to keep warm and whether this changes with an animal’s age. Of course, Williams is keeping records of her findings. They will be interesting because no one has systematically measured blubber thickness before!

Marine mammals enjoy special protection in the United States. Research on marine mammals (including photography) within U.S. jurisdictions or when based at a U.S. institution requires a permit under the U.S. Marine Mammal Protection Act. Bob Marstall, who took this photo, is listed on Dr. Randall Davis's permit, which is Marine Mammal Permit #821-1588-01.

Your friend,

Bob