Social organization in the Chinese water deer, Hydropotes inermis

The social organization of Chinese water deer was studied in a zoological park. Most adults lived together in the mixed zone, although other habitats were available. The overlap between individual areas was largest in females. In the mating season alone, less than half of the males established territories which overlapped in small spots where most encounters occurred. Females travelled freely throughout the entire available area, but non-territorial males stayed between the territories. Except in males during mating season, very few physical contacts other than sniffing took place between individuals regardless of age, sex or status. Each animal lived alone and did not show attraction or aggressiveness towards congeners. Grouping was temporary with no durable link between individuals, not even between mothers and daughters older than 5 months. The solitary life of individuals on a common ground and the establishment of seasonal territories make the water deer unique among ruminants. The species appears to be no more social than the water chevrotain, an “ancient” species. This fits well with other characteristics of the species.

This study was undertaken at the Branféré Zoological Park (Bretagne, France) with the help of the staff and all other personnel. Many thanks to Yves Philippot for the good work conditions and the collaboration offered. Many thanks also to Dr. M. Schlee, A. S. Cooke and one anonymous referee for the comments and corrections of the manuscript.

Authors and Affiliations

1. Muséum national d’histoire naturelle, EGB, UMR 7204, Ménagerie du Jardin des Plantes, 57 rue Cuvier, 75231, Paris Cedex 05, France

   Gérard Dubost, Florence Charron, Aurélie Courcoul & Aurélie Rodier

Corresponding author

Correspondence to Gérard Dubost.

Communicated by: Magdalena Niedziałkowska

Appendix: social behaviours in the Chinese water deer (Stadler 1990; Zhang 1996, this study)

Pacific interactions

• Sniffing: usually reciprocal; more often on the nose than on the rear of another individual by females (178 observations vs 68); more on the genital region of females than on their nose by males, particularly in birth season (53 vs 30); body sniffed only in mating season; sniffing of males on females more frequent than the reverse (0.027 ± 0.028 per female per hour vs 0.008 ± 0.012 per male per hour, respectively; t = 3.51, p < 0.001)

• Licking: never reciprocal; the individuals briefly lick the nose, body or rear of another.

Agonistic interactions

• Usually there is no threat between females, one of them surrendering its place if necessary. When a threat exists, it often consists in tongue flicking in vacuum, sometimes with aborted steps toward the partner, tail up, no kick.

Sexual interactions

• Approaches of female by male: neck stretched, nose close to the ground, emitting soft groaning calls. Usually, the male sniffs her rear or her place and makes 1–3 “flehmen” in succession with the nose raised, each lasting 2–5 s. When a female is lying down, it rapidly rotates its head several times from one side to the other, a behaviour characteristic of the species. It can also gently kick the female with a foreleg to make her stand up.

• Pursuit: usually by walking; the male rarely smells and never licks the genital region of the female; no tandem formation; sometimes, the male tries to retain the female on its territory; neither true pre-mounting sequence nor physical contact on the female with neck or leg (“Laufschlag”)

• Mount: The male lies on the female’s back and touches her shoulder laterally with the tip of its nose. The female can move slightly forward.

• Territorial males court females mainly in the maximum mating period (0.056 ± 0.020 courting/female/h vs none in the first and 0.014 ± 0.007 in the third period; U _5,5 = 0 and = 4, p < 0.01 and <0.05, respectively). Non-territorial males are more limited to the last period (0.060 ± 0.023 vs 0.005 ± 0.005 in the first and none in the second period, U _5,5 = 1 and = 0; p < 0.01).

Interactions between females and young

• Same interactions of females with unrelated as with their own young, although much less frequent; this concerned 1.3–15.7% of young living in the area of each female; no threat towards young; sniffing and attempts to suck of alien young concerned all focal females, licking four of five, and suckling three of five

• Sniffing: females sniff the nose more than the rear of the young (214 vs 103), which in turn often sniff the rear of females (21 of 37)

• Licking: females lick young with the same frequency on various parts of the body

• Attempt to suck: sometimes performed by the young when mothers were lying down or walking, few are successful

• Suckling: in an anti-parallel position, usually only one young at a time but two or more can suck on both sides of the female, blows of young with one foreleg to the female’s hind leg (“Milchtritt” or “milk step”), most suckling bouts ended by the female soon after the first week

Male territorial behaviour

• Rubbing of head against low branches, scratching the ground with a foreleg and defecation near territorial limits, often after interactions; territorial defence by parallel walking with legs stiff, head and neck raised, and the minute tail also raised; chases numerous with acute cries in succession; fight with each partner circling around its opponent for striking it with canines on the back; no kick.

• Non-territorial males live together at the same place and never defend the ground occupied; however, they sometimes show the same behaviours as territorial males, although less frequently, on average 2.33 ± 2.34 parallel walking in non-territorial males vs 5.86 ± 3.02 in territorial males during the maximum mating period (U _6,7 = 6.5, p < 0.05). They pass in proximity to other males without showing aggressive behaviour more often than did territorial males (U _6,6 = 1, p < 0.01). During encounters they are often defeated, whereas territorial males are usually victorious (U _6,7 = 8, p < 0.05).

Reprints and permissions