Giant Ground Sloth
Megalonyx cf. jeffersonii Desmarest
Description: The giant ground sloth, Megalonyx, is represented at Big Brook by its claw bones. There have been only a few
of these claws recovered. They are flattened and curved, gradually forming a blunt point. The claw cores are always missing
the claw sheaths, made of chitin. They are 19 cm (about 7.5 in) long and about 10 cm (about 4 in) wide.

There have been other parts of the skeleton, such as vertebra, have been found in other parts of the state. So far, there has
been no other identifiable material found at Big Brook or at least recognized.

Commonality: Any material from the ground sloth is rare.

Similar fossils: There are no similar fossils.

Size: Judging from the size of the claw core and comparing with complete skeletons found in other southern states, the giant
ground sloth was about the size of a modem horse, about 2.5 meters (about 7.5 feet) in length.

Notes: The presence of the giant ground sloth is inconsistent with the usual Ice Age fauna and probably existed during the
interglacial periods when the temperature was much like it is today. Even during the warm periods, New Jersey represented
the northeastern range of
Megalonyx. A claw that was found at Big Brook is presently on display in the New Jersey State
museum in Trenton.
Ground Sloth Claw Core
NJSM Specimen
Painting by Don Miller  at
Front View
Side View
Back View
Vertebra found on Holgate Beach, NJ
Ground Sloth Toe Bone
NJSM Specimen