STL Science Center

STL Science Center

11 September 2013

Choosing Wisely

There is so much interesting anatomy, I admit it as someone that does not enjoy studying mammals typically, to choose to discuss today that I am not sure if I want to look at the hindlimb or the nasal trunk of Leptictidium; we are probably lucky that I narrowed it down to those two anatomical features honestly. The hindlimbs of Leptictidium were specialized locomotive machines much like those present in extant kangaroos and rabbits. The kangaroo rat actually provides some very likely mechanics for the movement of Leptictidium through the underbrush.

The fact that it could hop at speed probably made evasion of predators its most likely defense mechanism and, depending on the musculature associated with individual specimens and species, the speed of the Leptictidium and range or types of predators able to chase down the little mammals was probably different in different ecosystems and time periods. To my knowledge mechanical studies have not been done comparing the speeds and gaits of different species of Leptictidium. It is probably important to note that the relaxed gait is not strictly representative of the speed of any individual within a species.

The nasal trunk of Leptictidium that is thought to exist in these small mammals would have more than likely contained some highly sophisticated olfactory senses as it was more a proboscis than it was an actively foraging trunk used for manipulating objects. The dedication of senses in the trunk would allow this small mammal to actively forage day or night and, with other heightened senses nocturnal life would have been an advantageous mode of life for Leptictidium. Considering, however, that the orbits do not seem to be exceptionally large or geared toward containing eyes that were adjusted to a nocturnal lifestyle, it appears to be more likely that Leptictidium was a crepuscular (dawn and dusk) predator of insects. Then as now insects would have been very active at dawn and dusk and Leptictidium could have used its heightened senses of smell and hearing to detect insects foraging at a distance and hidden by dense vegetation from the sight of Leptictidium.

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