Behavioral indices of estrus in a group of captive African elephants (Loxodonta africana)

Abstract

This study investigated behavioral signals of estrus by systematically monitoring the interactions of one male with four female African elephants housed in a naturalistic outdoor enclosure at Disney's Animal Kingdom over a period of 11 months. We measured changes in five spatial behaviors and 22 tactile-contact behaviors, as well as changes in serum progestagen and LH concentrations, across three ovarian cycles for each female. Two females did not cycle during the study. Three different phases of the ovarian cycle were identified: mid luteal, anovulatory follicular, ovulatory follicular. The male followed more and carried out more genital inspections, flehmen, and trunk-to-mouth behaviors toward cycling females during their ovulatory phase. Genital inspections by the male peaked above baseline levels on the day of an LH surge, and up to 9 days before, in both cycling females and, thus, might be a useful behavioral index of estrus. The male also carried out more genital inspections, flehmen, and trunk touches to the back leg toward ovulatory cycling than noncycling females. Overall, our results indicated that: 1) a single subadult African elephant male could discriminate two females in the ovulatory phase of their cycle (i.e., during the 3 weeks preceding ovulation) from the mid luteal phase; 2) the male also discriminated two cycling females in the ovulatory and anovulatory follicular phases from two noncycling females; 3) two females in the Alessia Ortolani's present address is Dip.

Estrous state influences on investigative, aggressive, and tail flicking behavior in captive female Asian elephants

“…Behaviors such as the estrous walk and interest by males appear only days before consort establishment or require the presence of a male [Moss, 1983;Ortolani et al, 2005]. Determining female reproductive state in a noninvasive manner well in advance of mating would be a valuable tool for studies on communication and sexual selection.…”

Vocal communication in African Elephants (Loxodonta africana)

“…Males may monitor their auditory environment for these preovulatory ''estrous rumbles,'' which attract them to groups containing cycling females. Once present, males can switch to other sensory modalities, such as olfaction, to test for current fertility [Rasmussen and Schulte, 1998;Ortolani et al, 2005]. In addition, females may also rumble at this stage to incite male-male competition [Poole, 1989].…”

Fecal 20-oxo-pregnane concentrations in free-ranging African elephants (Loxodonta africana) treated with porcine zona pellucida vaccine

“…In the female African elephant (Loxodonta africana), estrous cycle length is reported to range between 13 to 17 weeks [17][18][19][20][21][22][23][24][25]. The cycle is divided into a 4 to 6 week follicular phase after 4 which an increase in progesterone levels, believed to trigger ovulation, marks the onset of an 8 to 11 week luteal phase [17,[20][21][22].…”

“…However, Delsink et al [11,16] found no significant change in core and total range use, matriarchal status, cow/calf interaction, herd fragmentation/isolation, musth occurrence, bull hierarchy, and no aberrant or unusual behaviour witnessed among the herds. Furthermore, concerns were raised as to the potential effect of the pZP vaccine on luteal function, but to date, there has been no attempt to examine endocrine correlates associated with pZP vaccine use in African elephants.In the female African elephant (Loxodonta africana), estrous cycle length is reported to range between 13 to 17 weeks [17][18][19][20][21][22][23][24][25]. The cycle is divided into a 4 to 6 week follicular phase after 4 which an increase in progesterone levels, believed to trigger ovulation, marks the onset of an 8 to 11 week luteal phase [17,[20][21][22].…”

“…Phase length estimates as well as ovarian cycle length estimates are given as mean ± SD. Females were categorized as having an irregular cycle when overall cycle length exceeded or fell short of the reported norm of 13 to 17 weeks [10,[17][18][19][20][21][22][23][24][25]. The non-cycling category was reserved for females who had no identifiable pattern in 5-pregnan-3-ol-20-on concentrations throughout the study period [46].…”