According to the journal kept by William Clark, the expedition encountered its first prairie dog on September 7, 1804. They commenced trying to catch the animals, and in the process killed one and caught another one alive. Throughout their expedition, they were tasked by President Thomas Jefferson with taking specimens of the flora and fauna of the region. The prairie dogs were fascinating to Lewis and Clark because they were so adept at burrowing. Clark relates that the men dug nearly six feet into the hard clay ground without breaching their tunnels. In some tunnels, Clark says, they dumped "5 barrels of water without driving [sic] them out." Once they captured the little animal, Clark describes its appearance as a sort of combination of a rabbit, dog, and ground squirrel. It had a mouth like a rabbit, eyes reminiscent of a dog, and a tail like a squirrel, which they would "Shake and make chattering noise." While investigating (or, more accurately, laying waste to) the prairie dog village, they killed a rattlesnake with one of the creatures in its stomach.