Erin Pickett at UC Santa Cruz, Long Marine Lab--You are what you eat, and well, so are elephant seals. At least as far as whiskers go- whisker composition changes with diet. There are a few biologists in the Costa lab studying diet using stable isotopes of whiskers. Last Spring five satellite tagged females were given a dose of an amino acid called glycine. Glycine is found naturally in the proteins of animals. Glycine made in the lab is full of nitrogen 15, a heavier version of a seal's biosynthesized nitrogen.

Huh?! Basically, when the seal was given nitrogen, a spike in N15 will show up in the growing whisker. The process is similar to nicking the whisker and watching the nick move toward the tip of the whisker as it grows, only the nick is within the whisker itself. Pretty cool!

So, who has time to watch a whisker grow? Personally I wouldn't mind lying on the beach in the middle of an elephant seal harem full of protective mothers and violent males, weathering the winter rain and wind while trying to keep track of which whisker I was watching and how fast it was growing (I hope you sense my sarcasm here... that sounds pretty dangerous!). But lets be realistic- elephant seals only spend about 2 months out of the year on the beach. We don't know what they are doing the rest of the time. Foraging most likely, but where and on what??

Where are these guys going?? Here, a beach full of juveniles molt at Año Nuevo State Reserve; a similar whisker isotope study, focused on juvenile seals,  is being conducted by Costa lab Graduate student Nicole Teutschel. Photo: Erin Pickett

Two doses of glycine (one last spring, and one this winter) will leave two separate marks deep within the whisker. " Two spikes will be better than one to indicate if growth is constant ", PhD student Jason Hassrick says. Jason Hassrick is the graduate student heading up the e seal whisker growth rate project. After the seals molt this spring, a whisker will be collected and sent to a lab to be analyzed. This whisker will tell us two important things: its growth rate, discussed here, and the seals diet. Determining the diet of a seal that dives as deep as 2000 meters is not something that can be done easily through observation, but it can be looked at through stable isotope analysis. We won't know specifically what species of fish or squid the seals are feeding on, but we will know where the seals are eating within the food web.

This recently deployed tag will (hopefully) stay with this seal until she returns to Ano this spring to molt. Check out her big whiskers. Photo: Erin Pickett

And after all of this? We can compare the two of course! This will not only allow us to determine what the seal was eating, but when it ate a squid, and when it ate a fish. The last element of this experiment, and maybe the most important in terms of the bigger picture is what makes this project a unique one. These seals, like most of the others studied by the Costa lab, are equipped with satellite tags, time-depth recorders, salinity and temperature sensors.

Nicole Teutschel attaches a VHF tag on this female's back using epoxy. Photo: Erin Pickett

A seal with expensive whiskers and expensive tags is in fact priceless, according to Hassrick. Mirounga Angustirosis is a unique species in many ways; its foraging and fasting abilities distinguish it from many marine mammals. Professor Dan Costa discusses the seals on NPR, " ...in many respects you could argue that these deep diving animals are the ones that will be most sensitive to environmental change". Prey abundance and distribution will change naturally during events such as El Niño but we don't know if climate change will bring more severe disruption, and how these seals will deal with it.

Groups of seals and other marine animals such as seabirds and sharks are known to congregate around the same areas to feed, biological hotspots where food is abundant and easy to catch. It is likely that climate change may disrupt these sensitive habitats, unraveling food webs completely or relocating predators and prey across the globe. The more we know about them the better we can protect them.

Jason's glycine study and the Costa lab's tagging efforts are a part of TOPP's larger endeavor to explore the world's oceans. Whiskers, though small, are a part of this.