In 2015 and 2016, six team members from the University of Montana and the University of Hawaii made two-month trips to McMurdo Station, Antarctica ("The Ice") to study the behavior, physiology, and ecology of Antarctic sea spiders (pycnogonids).  Please explore this web page to find out all sorts of information about our research on these fascinating animals!

In 2016 we were joined by a PolarTREC teacher, Tim Dwyer. PolarTREC (Teachers and Researchers Exploring and Collaborating) is a program designed to offer 6-12 teachers the chance to experience and work in Antarctica. Tim Dwyer is a high school science teacher from Friday Harbor, Washington and he maintained a blog about his experiences in Antarctica and working with our research group. His blog posts can be seen HERE!

What is polar gigantism?

Many marine animals show unusual patterns of body-size evolution: species that live in polar waters tend to be larger than relatives living in temperate or tropical waters. This pattern is called 'polar gigantism' and we want to know why and how this happens. We're focusing our research on sea spiders (technical name is pycnogonids) because they're well known to follow this rule. Many Antarctic species are enormous. Our research compares the physiology and biomechanics of these polar giants to related species from other places in the world.

What are pycnogonids?

Pycnogonids, a.k.a. "sea spiders," aren't true spiders, although the two groups are somewhat related. Pycnogonids are generally placed within the subphylum Chelicerata, which also contains the horseshoe crabs and arachnids (spiders, ticks, mites, scorpions, etc.), although some recent studies suggest that pycnogonids are an even more ancient group. 

This research is funded by the Office of Polar Programs at the National Science Foundation.

Caitlin Shishido Measures the rate of oxygen consumption BY a pycnogonid

We are testing the idea that where large and small sea spiders occcur in the world reflects how easy it is for them to get enough oxygen. We think that having a really large body (=polar gigantism) is possible in the frigid ocean surrounding Antarctica because getting oxygen is easier in polar seas than it is elsewhere in the world.

Bret Tobalske testing the associated drag on a pycnogonid in a water flume

Gigantism in sea spiders has seemingly evolved as a trade-off between the need for a thin cuticle to facilitate diffusion and the need for mechanical support of the body.  We will test the strength of their body design in a variety of ways on location under the ice as well as in a flow tank in a lab at McMurdo Station.

STEven lane training under the ice at lake MCGregor, Montana, USA

Sea spiders live on the sea floor, and many are quite cryptic and hard to find. We look for them them on SCUBA by searching in places they like to hang out--on hydroids, anemones, and other soft-bodied animals.