TIMOTHY R. DWYER, COURTESY OF ARCUSMost animals pump blood through their hearts. Not sea spiders—these ocean-dwelling arthropods pump blood through their guts, according to a study published today (July 10) in Current Biology.
Sea spiders, which range in size from around a millimetre long to the size of a large dinner plate, have relatively tiny torsos and six pairs of long, lanky legs. For these creatures, legs are for more than getting around—they also contain their gonads and guts that branch down each of their limbs. “They have to do most of their business in their legs,” study coauthor Amy Moran, a marine ecologist at the University of Hawaii at Manoa, tells The Atlantic.
“Unlike us, with our centrally located guts that are all confined to a single body cavity, the guts of sea spiders branch multiple times and sections of gut tube go down to the end of every leg,” coauthor Arthur Woods of the University of ...