Otter Den Cave and Deer Bone Cave

Cavers Pete Smith (behind) and Steve Lewis (yellow suit) at the entrance of Otter Den Cave. Deer Bone Cave is farther down the base of the cliff to the right.

Near the southeastern coast of Coronation Island at an elevation of 300 meters above sea level are two small den caves, located at the base of a west-facing cliff (see photo at left). Each extends back about 10 meters and has a soft, dry, horizontal dirt floor that appears to be the top of a thick sediment deposit. Both have been used as otter dens and contain large volumes of bone in the sediment.

Deer Bone Cave is the larger of the two and has a crawlway entrance that is easy to enter. Inside are thick accumulations of fish and bird bones from otter scat as well as deer bones scattered about. At the back of the cave is a depression with several sticks in it--apparently the remains of an otter den. This cave would have made an ideal bear den (similar to those found on Prince of Wales Island) at the time when bears lived on Coronation Island.

Otter Den Cave is difficult to enter because the tight entrance crawlway is surrounded by a mound of dirt and rock that has fallen from the cliff above. Inside the cave the ceiling remains low, but the passage is easy to crawl through. This cave also contains a vast bone deposit (mostly fish but also small birds and mammals), and it appears to have been inhabited by otters much more recently than Deer Bone Cave. One pile of scat appeared quite fresh, and there were three well-preserved otter nests--shallow depressions 0.5 meters in diameter containing a bed of sticks and moss (see photo at right).

Surface sediment samples were collected by Dr. Heaton when these caves were visited in the summer of 2001, but they have not yet been studied extensively. The surface bone is probably very recent. But the structure of these caves makes them ideal as carnivore dens, and they appear to have been subject to long-term sediment accumulation (both from biologic and inorganic processes). Otter Den Cave may have had a much larger entrance before the debris accumulated at its entrance. If foxes or bears used these caves as dens around the time of the Last Glacial Maximum (as they did at On Your Knees Cave), they may contain extensive fossil deposits of great antiquity. The next step will be to excavate test pits to see if this is so.

© 2002 by Timothy H. Heaton