Urine musth

To begin the assessment of possible chemical messages between male Asian elephants, responses of captive males to conspecific musth and nonmusth urine were measured. Some obvious disadvantages of captive studies are substantially offret by some real advantages (1) close, accurate behavioral observations in a limited-size enclosure, (2) precise placement of test samples on substrate free of conflicting signals, (3) safe collection of test samples of elephant origin from males whose hormonal status can subsequently be determined. 

For this study 500 ml urine samples were collected both during musth and nonmusth periods from two mature male Asian elephants and frozen for subsequent tests. Concurrent serum samples retroactively established circulatory testosterone concentrations of the donor male pertinent to the collected urine aliquots (Table 1) by Dr. David Hess of the Oregon Regional Primate Center using a previously described methodology (Rasmussen et al., 1984). 

Our previous studies established that a 150 ml aliquot is sufficient to elicit chemosensory responses (Scott et al., 1997). For a bioassay series, two 500 ml aliquots—one from a male in musth and the second from a male not in musth—were thawed at 20°C and then subdivided into three equal volumes. These sub-aliquots were subsequently presented to one male at a time, as paired samples, plus the water control for a total of three samples per assay. Thus, presentations were aliquots of musth urine, nonmusth urine, and tap water, a visual control. Logistically we did not have the financial resources to freeze the urine collected at -80°C. Freezing at -20°C certainly maintained the integrity of most bioactive urinary compounds, and the purpose of this study was to compare responses to musth versus nonmusth urine. The tight control... 

To monitor vomeronasal organ system responses, we examined the rate of flehmen responses relative to each approach to the samples. Flehmen responses per approach to each of the urine samples by subadults (n=2) and the adults (n=3) in the study were compared. The subadults performed flehmens at a greater rate to musth compared to nonmusth urine and at an overall greater rate compared to the adult responses (Figure 2). 

Results from the relative time spent investigating each sample demonstrate that the captive male Asian elephants in this study used chemical signals in urine to distinguish between musth and nonmusth urine. The males spent more time investigating the musth urine samples, perhaps to assess the relative dominance of the donor and status as a potential competitor for mates. Olfactory investigation of nonmusth urine shows that there are additional chemical signals other than those related to musth state present in excretions. 

Figure 2 Mean flehmen responses per approach to musth and nonmusth urine by two age classes of male elephants...

I familiar musth urine I unfamiliar musth urine... 

Figure 3 Mean sum of olfactory responses (C+P+F) per approach to musth and nonmusth urine from familiar and unfamiliar donors and a control by 2 subadult and 3 adult male elephants (+/- SE)...

Subadult males may perform more flehmen responses than adults as they acquire information for their olfactory memory and learn more of their surroundings. Adult males may easily recognize the urinary chemical signals indicative of musth, while subadult males need repeated exposure to their VNO system to fully assess a urine sample for the musth state and identity of the donor. 

In addition to musth state, chemical signals may include individual recognition or recognition of familiarity. Responders unfamiliar to the urine donor performed more olfactory and pre-flehmen responses than familiar responders. This was most dramatic in the subadult age class. Future research could examine how long this increased response is maintained before the responses decrease to the response frequencies observed to familiar urine. Fiulher examination of urine bioactivity could reveal any influence a male s own musth state has on his olfactory interest in musth urine from male conspecifics. The temporary increase in relative dominance acquired by a male in musth may alter a male s olfactory investigation of musth urine con ared to when he is not in musth. 

Rasmussen, L. E. L., 1988, Chemosensory responses in two species of elephants to constituents of temporal gland secretion and musth urine, J. Chem. Ecol. 14(8) 1687-1711. 

Scott, N. L., Schulte, B. A., Mellen, J. D., and Rasmussen, L. E. L., 1997, Do Male Asian Elephants (Elephas maximus) Advertise Musth in their Urine American Society of Mammalogists, Stillwater, Oklahoma. 

Significant differences ANOVA, pair-wise multiple comparisons using the student-Newman-Keuls method, p = 0.05. stage of musth period when urine dribbling is occurring. 

Scott, N.L., Schulte, B.A., Mellen, J.D. Rasmussen, L.E.L. 1997. Do male Asian elephants Elephas maximus) advertise musth in their urine American Society of Mammalogists Meeting, Stillwater, OK, June 1997. 

In our data analyses the behavioral parameters and chemical data obtained in this study helped us to derive four approximate, although intergrading states. These states were called premusth, early musth (indicated by temporal gland secretion), heavy musth (indicated by concurrent temporal gland secretion and urine dribbling), and postmusth. Premusth and postmusth were defined relative to the single musth period over which data were collected from Packy (see Results). 

Figure 1. Deviant behavior (O) and serum testosterone concentration ( ) of a captive Asian bull elephant (Packy, 32 years old) throughout a musth episode (premusth through postmusth). Deviant behavior was the weekly mean of five individual behaviors each graded on a 0-4 scale daily. Serum testosterone (ng/ml) was measured weekly. Solid arrows indicate start and end of temporal gland secretion (TGS), which was delineated as the musth period. The dashed arrow indicates the beginning of urine dribbling (cessation was simultaneous with end of TGS).

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