Physical, Physiological, and Behavioral Correlates of Musth in Captive African Elephants (Loxodonta africana)

Although musth in male African elephants (Loxodonta africana) is known to be associated with increased aggressiveness, urine dribbling (UD), temporal gland secretion (TGS), and elevated androgens, the temporal relationship between these changes has not been examined. Here, we describe the pattern of musth‐related characteristics in 14 captive elephant bulls by combining long‐term observations of physical and behavioral changes with physiological data on testicular and adrenal function. The length of musth periods was highly variable but according to our data set not related to age. Our data also confirm that musth is associated with elevated androgens and, in this respect, show that TGS and UD are downstream effects of this elevation, with TGS responding earlier and to lower androgen levels than UD. Because the majority of musth periods were associated with a decrease in glucocorticoid levels, our data also indicate that musth does not represent a physiological stress mediated by the hypothalamic‐pituitary‐adrenal axis. Furthermore, we demonstrate that the occurrence of musth is associated with increased aggression and that this is presumably androgen mediated because aggressive males had higher androgen levels. Collectively, the information generated contributes to a better understanding of what characterizes and initiates musth in captive African elephants and provides a basis for further studies designed to examine in more detail the factors regulating the intensity and duration of musth.

[1]  J. Hodges,et al.  Patterns of urinary and fecal steroid excretion during the ovarian cycle and pregnancy in the African elephant (Loxodonta africana). , 1999, General and comparative endocrinology.

[2]  G. A. Lodge,et al.  Serum testosterone and musth in captive male African and Asian elephants , 1990 .

[3]  M. Schmidt,et al.  Testosterone and dihydrotestosterone concentrations in elephant serum and temporal gland secretions. , 1984, Biology of reproduction.

[4]  N. Place,et al.  Seasonal changes in plasma testosterone and glucocorticosteroids in free-living male yellow-pine chipmunks and the response to capture and handling , 2000, Journal of Comparative Physiology B.

[5]  W. Ratnasooriya,et al.  Testosterone secretion, musth behaviour and social dominance in captive male Asian elephants living near the equator. , 1996, Journal of reproduction and fertility.

[6]  J. Poole Mate guarding, reproductive success and female choice in African elephants , 1989, Animal Behaviour.

[7]  J. Eisenberg,et al.  Reproductive Behavior of the Asiatic Elephant , 1971 .

[8]  B. Shuter,et al.  The value of ultrasound, gonadotropin, and estradiol measurements for precise ovulation prediction. , 1982, Fertility and sterility.

[9]  K. Shimizu,et al.  Endocrine Correlates of Rank, Reproduction, and Female-Directed Aggression in Male Japanese Macaques (Macaca fuscata) , 2002, Hormones and Behavior.

[10]  J. Hodges,et al.  Assessment of testicular endocrine function in captive African elephants by measurement of urinary and fecal androgens , 2002 .

[11]  J. Poole,et al.  Musth and urinary testosterone concentrations in the African elephant (Loxodonta africana). , 1984, Journal of reproduction and fertility.

[12]  D. Hess,et al.  Chemical Profiles of Male African Elephants, Loxodonta africana: Physiological and Ecological Implications , 1996 .

[13]  R. Frydman,et al.  Interpretation of plasma luteinizing hormone assay for the collection of mature oocytes from women: definition of a luteinizing hormone surge-initiating rise. , 1981, Fertility and sterility.

[14]  R. Palme,et al.  Non-invasive assessment of adrenocortical function in the male African elephant (Loxodonta africana) and its relation to musth. , 2003, General and comparative endocrinology.

[15]  N. Place,et al.  Relation of glucocorticosteroids and testosterone to the annual cycle of free-living degus in semiarid central Chile. , 1999, General and comparative endocrinology.

[16]  S. Holm A Simple Sequentially Rejective Multiple Test Procedure , 1979 .

[17]  M. Meaney,et al.  Testosterone-dependent variations in plasma and intrapituitary corticosteroid binding globulin and stress hypothalamic-pituitary-adrenal activity in the male rat. , 2004, The Journal of endocrinology.

[18]  B. Shuter,et al.  The value of ultrasound, gonadotropin, and estradiol measurements for precise ovulation prediction , 1982 .