Exp. Anim.34(1), 63-66, 1985

•\ Note•\

Gestation Period of the Laboratory Reared Volcano Rabbit

(Romerolagus diazi)

Tetsuya MATSUZAKI, Masao KAMIYA* and Hiroshi SUZUKI**

Central Institute for Experimental Animals, 1430, Nogawa , Miyamae, Kawasaki 213, Japan, *Department of Parasitology , Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060, and **Department of Virology, Institute for Tropical Medicine, Nagasaki University, Nagasaki 852.

(Received 21 March 1984 / Accepted 24 August 1984)

The period of gestation of the volcano rabbit (Romerolagus diazi) was measured. Females were cohabited within one hour after confirmation of coitus or were separated from the males after cohabiting overnight . In 12 females which gave birth 20 times in total, the gestation period was 39 days in 35% , 40 d ays in 50% and 41 days in 15% ; 85% of animals showed a gestation period of 39 or 40 days.

Each species of mammals has a specific separated from the males within one hour gestation period but it has been confirmed after confirmation of coitus or from the only in species which are reared by man. day when the females were removed after As previously reported [5], the author suc- cohabiting overnight (5 : 00p. m. to 9 : 00a .m.) ceeded in laboratory rearing and reproduc- by counting the day of confirmation of tion of wild volcano rabbits (Romerolagus coitus as day 0. diazi) obtained from Mexico, and reprodu- Table 1 shows the period of gestation ction is being continued to develop volcano calculated for 12 females which underwent rabbits into laboratory animals. This report a total of 20 deliveries. These dams were gives the results of a study. on the gesta- limited to those which nursed and weaned tion period of volcano rabbits and a their offspring. The gestation periods of comparison with gestation periods of other the volcano rabbits observed in this study animals of the order Lagomorpha. were from 39 to 41 days, i. e. 39 days in The animals used were one female and 35%, 40 days in 50% and 41 days in 15% . two males captured and introduced into Therf ore, 85% of the total animals showed my laboratory in 1979, eight females and a gestation period of 39 or 40 days. These four males of her offspring, and three results were in close agreement with the females captured and introduced in 1983. author's previous results [5] and with Mating was performed by cohabiting the those of Juarez et al. [2]. All of these females with males. Among the cohabited results assume that the gestation period pairs, the gestation period was calculated of volcano rabbits ranges from 38 to 41 from the day when the females were days. 64

Table 1. Gestation period of volcano rabbits reproduced in the laboratory

I: Wild volcano rabbit captured at Parres in the suburbs of Mexico city in 1979 II-III: Offspring obtained from I (F1) IV-VII and IX: Off spring obtained from II (F2) XII: Offspring obtained from IV (F3) VIII, X and XI: Wild volcano rabbits captured in 1983. VIII and XI were captured in Parres and X in Juchitepec

The gestation period of volcano rabbits rabbit [1, 8]. The gestation periods of the were compared with those of six species Amami rabbit (Pentalagus f urnessi) and of Lagomorpha as shown in Table 2. The the red rock rabbit (Pronolagus crassicau- gestation period of the pikas [4, 7, 9] is d atus) which belong to the same subfamily shorter than those of the volcano rabbit, as the volcano rabbit are of great interest, hare and European rabbit. The period of but they are still unknown. the hare [3,6] differs from that of the This report has examined the gestation volcano and European rabbits. The gesta- period, one of the physiological values tion periods of European rabbit (Oryctolagus which must be clarified for the development cuniculs, ver, domesticus) such as the New of the volcano rabbit as a laboratory Zealand White, Dutch, Himalayan, Japanese animal. It is not certain if the gestation White and Angora rabbits, which have periods of animals are decided in accordance long heen used as experimental animals with the genus or the species, but the also differed from that of the volcano gestation periods of the above seven spec- 65

Table 2. Comparison of gestation period between volcano rabbits and six species of the order Lagomorpha

a: Tohoku hare, b: Kyushu hare, c: New Zealand White , Dutch, Himalayan, Japanese White and Angora rabbit belong to this species, d: Numbers in parentheses show the percentage of cases observed.

ies, including subspecies, of Lagomorpha [2] Juð•rez, D., and Zulbarð•n, R. (1983). Estudio sobre were all different. The gestation period of el Crecimiento y la Reproduccion del Conejo de volcano rabbits was 39 or 40 days in 85% los Volcanes (Romerolagus diazi) Silvestre en el Laboratorio. Universidad Nacional Autð®noma de of the cases observed, and a more definite Mð¥xico, Facultad de Ciencias. figure should be obtained in the future as [3] Kumekawa, S. (1982). Animals and Zoos, 9, 27. more animals are observed. [4] Matsuzaki, T., Saito, M., Yamanaka, M., Esaki, K., and Nomura, T. (1980). Exp. Anim ., 29, 165- 170. The author wishes to thank Drs. R. [5] Matsuzaki, T., Saito, M., and Kamiya, M. (1982). Villa, H. Granados, J. Torres and A. Salas Exp. Anim., 31, 185-188. for their cooperation in the capture of the [6] Otsu, S. (1972). Exp. Anim., 22 Supplement, 237- 244. volcano rabbits in Mexico in 1979 and 1983. [7] Puget, A. (1973). Lab. Anim. Sci., 23, 248-251. [8] Riched, R. F. (1974). In The Biology of the Lab- References oratory Rabbit. pp.1-29. Steven, H. W. Ronald , E . F., and Alan, L. K. (edit), Academic Press Inc ., [1] Fujii, T., Sasaki, H., and Watanabe, T. (1968). New York, San Francisco and London. Exp. Anim., 17, 59-62. [9] Severaid, J. H. (1950). I. Mamm., 31, 356-357. 66

実 験 室 内飼 育 メ キ シ コ ウ サ ギ(Romeyolagus diazi)

の 妊 娠 期 間

松 崎 哲 也 ・神 谷 正 男*・ 鈴 木 博**

(財)実 験動物中央研究所 *北 海道大学獣医学部家畜寄生虫病学教室 **長 崎 大 学 熱 帯 医 学 研 究 所 ウ ィル ス 学部 門

メ キ シ コ ウサ ギ(Romerolagus diazi)の 妊 娠 期 間 に せ た メ ス 親,計12匹 の 延 べ20回 の 出 産 例 に よ る 妊 娠 期 間 つ いて 調 べ た。 交 尾 確 認 後1時 間 以 内 に オ ス と分 離 した は39日(35%),40日(50%),お よ び41日(15%)で, メ ス親,お よ び交 尾 確 認 後 引 き続 き1夜 オ ス と同 居 を さ 39日 と40日 群 が 全 体 の85%を 占 め た 。