Exploring the links between bite force, body mass, and exploratory
behavior in the naked mole rat, Heterocephalus glaber.
Abstract
Biting strength combined with exploratory behavior gives animals the
ability to interact with their environment. African mole rats have a
well-developed biting apparatus and perform cooperative tasks that are
mostly related to their exploratory behavior. However, the hypothesis
that body mass and strength are related to activity and exploration
remains to be confirmed in this taxon. The aim of this study was to
examine the relationship between bite force and body mass, as well as to
explore potential correlations between these factors and exploratory
behavior in Heterocephalus glaber. To do so, we measured the bite
force and body mass of 79 young adult male and female naked mole rats
from a single captive colony, including the queen. We then observed and
quantified their exploratory behavior using an open field test during
which they could freely enter a new environment, in the form of a new
pipe linked to the housing colony. We showed that strength was
correlated with mass, which in turn was associated to age. Our
observations revealed that not all individuals engaged in exploration,
and that those who did tended to be the strongest. We found that
stronger and heavier individuals exhibited shorter entry latencies while
those who explored most extensively were typically weaker, lighter and
younger. Moreover, stronger and younger individuals frequently made more
trips back and forth. We compare these results with findings in other
species and discuss their implication in relation to interindividual
variability, boldness, and social organization within this species.