The dark-ventral-patch of male red deer, a sexual signal that conveys the degree of involvement in rutting behavior

In polygynous mammals, signaling may play a decisive
role in mating behavior, mediating the intensity of male fights and female mate
choice. During the rutting season, male red deer may show a visible dark patch
in their ventral fur. Recently, this patch has been suggested to act as a
flexible sexual signal, due to its relationships with other variables such as
age, body size, antler development, volatile compounds or the competitive
environment. The analysis of fur pigmentation at the
ventral patch suggests that this might also visually indicate the intrinsic
predisposition to fight. To assess the possible role of this trait as a
communicative signal, we hypothesized that the dark ventral patch in male
Iberian red deer (Cervus elaphus
hispanicus) is related to rutting behavior and mating success. Consistent
with our predictions, we found in a
field study that males with large dark patches showed a higher frequency of
rutting behaviors (mainly roaring and flehmen), and more interactions with
females and also attained larger harem sizes. Moreover, the dark ventral patch
was a better predictor of male behavior than antler tines or territory holding,
thus standing as a short-term indicator of male' willingness to invest in
breeding competition.