References and Notes Inbreeding and Juvenile Mortality in 1. M. Saginor and R. Horton, Endocrinology 82, 627 (1968); R. M. Rose, T. P. Gordon, I. S. Bernstein, Science 178, 643 (1972); K. Purvis Small Populations of Ungulates and N. B. Haynes, J. Endocrinol. 60,429 (1974); F. Macrides, A. Bartke, F. Fernandez, W. Abstract. Juvenile mortality of inbred young was higher than that of noninbred D'Angelo, Neuroendocrinology 15, 355 (1974). 2. C. B. Katongole, F. Naftolin, R. V. Short, J. young in 15 of 16 species of captive ungulates. In 19 of 25 individual females, belong- Endocrinol. 50, 457 (1971). ing to ten species, a larger percentage of young died when the female was mated to a 3. F. Macrides, A. Bartke, S. Dalterio, Science 189, 1104 (1975); J. A. Maruniak, A. Coquelin, related male than when she was mated to an unrelated male. F. H. Branson, Biol. Reprod. 18, 251 (1978). 4. J. A. Maruniak and F. H. Bronson, Endocrinol- ogy 99, 963 (1976). An ever increasing number of the adults (1-3). Inbred animals are usually 5. I. Martin, Psychol. Bull. 61, 35 (1964); R. F. Thompson and W. A. Spencer, Psychol. Rev. world's ungulate species exist only in "less able to cope with their environ- 73, 16 (1966); R. A. Hinde, in Short-term relatively small populations in which ment than are noninbred animals" (2, p. Changes in Neural Activity and Behavior, G. Horn and R. A. Hinde, Eds. (Cambridge Univ. some degree of inbreeding will inevitably 215) and are often more susceptible to Press, Cambridge, 1970), p. 3. occur. Extensive studies of laboratory various diseases and environmental 6. In our cannulation procedure, an atrial cannula (inner diameter, 0.30 mm; outer diameter, 0.64 and domestic mammals and birds in- stresses (3, 4). The limited data from nat- mm; 45-cm Silastic tubing, Dow Corning Corp.) exits via a backpack sutured to the mouse and is dicate that inbreeding leads, in the ma- ural populations suggest that close in- protected by an extension spring. The entire unit jority of cases, to increased mortality in breeding has the same deleterious con- is supported from above and swivels freely. During the 5-day surgical recovery period, 0.33 young animals and reduced fertility in sequences in the wild (5). units of heparin in 0.3 ml of saline is continuous- ly infused per 24 hours. Data to be presented elsewhere (10) document that cannulated males Table 1. Juvenile mortality in inbred and noninbred young. exhibit normal aggressive and sexual behaviors, when compared with males that do not have Non- In- 2 surgery. X test Sign Species inbred bred TV 7. The CF-1 mice used in this experiment were test* reared in our laboratory colony. At weaning (21 young young X2 P to 23 days of age), the males were isolated in 29 by 18 by 13 cm polypropylene cages in a room Elephas maximus (Indian elephant) without females. The ambient conditions were 23° ± 10C, 14:10 hour light-dark cycle, lights on Lived 11 2 19 + at 0600 hours, and Purina mouse chow and wa- Died 2 4 4.997 .025! ter always available. Experimental males were Equus burchelli (zebra) 70 to 80 days old. After cannulation, they were Lived 20 3 32 .413 + housed in 29 by 14 by 14 cm wooden boxes and .528! remained in the same room. All testing began Died 7 2 between 0900 and 1100 hours. Choeropsis liberiensis (pygmy hippopotamus) 8. After each 25-jitl blood sample was obtained, the Lived 139 23 235 17.28 .ooot + cannulas were rinsed and the blood was re- placed with heparinized saline (10 units per mil- Died 45 28 liliter). The 10-^1 samples of plasma were stored Muntiacus reevesi (muntjac) in 40-fil radioimmunoassay (RIA) buffer at Lived 18 12 40 1.212 .270 + —80°C before assay. Plasma LH concentrations Died 4 6 were determined with the NIAMDD rat radioim- munoassay kit verified for measuring mouse go- Cervus eldi thamin (Eld's deer) nadotropins by W. G. Beamer, S. M. Murr, and Lived 13 0 24 11.679 .001! + I. I. Geschwind [Endocrinology 90, 823 (1972)]. Died 4 7 The reference curve was fitted and the unknown concentrations were interpolated by using the Elaphurus davidianus (Pere David's deer) computer analysis described by D. Rodbard and Lived 15 19 39 .030 .857 + D. M. Hutt [in Symposium on Radioimmunoas- Died 2 3 say and Related Procedures in Medicine (Inter- Rangifer tarandus (reindeer) national Atomic Energy Agency, Vienna, 1974), p. 165]. Within-assay variation was 10.4 percent Lived 19 9 50 2.538 .107 + and between-assay variation 13.9 percent; the Died 10 12 minimum detectable amount was 0.125 ng. Re- Girajfa camelopardalis (giraffe) sults are expressed as nanogram-equivalents of NIAMDD-RAT-LH-RP-1. Lived 11 2 19 2.537 .107 + 9. H. R. Nankin and P. Troen, J. Clin. Endocrinol. Died 3 3 33, 558 (1971); A. Bartke, R. E. Steele, N. Mus- Tragelaphus strepsiceros (kudu) to, B. V. Caldwell, Endocrinology 92, 1223 Lived 10 8 - (1973). 25 .005 .941 10. A. Coquelin and F. H. Bronson, in preparation. Died 4 3 11. Analysis of variance with repeated measures Tragelaphus spekei (sitatunga) was performed on the peak LH values which Lived 15 31 75 9.012 .006t + were observed during the four sampling periods. Within both patterns of repetitive female ex- Died 1 28 posure, (-tests were used to compare the peak Hippotragus niger (sable) LH values observed during the first and fourth Lived 18 3 32 8.183 .005! + sampling periods; the /-test between the con- tinuous exposure and repetitive exposure groups Died 4 7 compared the peak LH values during the last Oryx dammah (scimitar-horned oryx) sampling period. Lived 35 0 42 28.378 .ooot + 12. R. E. Whalen, cited by J. R. Wilson, R. E. Died 2 5 Kuehn, F. A. Beach, J. Comp. Physiol. Psy- chol. 56, 636 (1963). Connochaetes taurinus (wildebeest) 13. J. O. Almquist and E. B. Hale, Proc. Congr. An- Lived 6 29 48 .680 .419 + im. Reprod. 3, 50 (1956); H. Fowler and R. E. Died 1 12 Whalen, J. Comp. Physiol. Psychol. 54, 68 Madoqua kirki (dik-dik) (1961); T. E. McGill, J. Genet. Psychol. 103, 53 (1963); R. P. Michael and D. Zumpe, Science Lived 10 7 32 .473 .499 + 200, 451 (1978). Died 7 8 14. We are grateful to C. Desjardins for his consid- Gazella dorcas (Dorcas gazelle) erable effort and direction during development of the cannulation procedure and to M. Graham Lived 36 17 92 9.288 .003! + for his assistance with computer analysis of Died 14 25 RIA. This investigation was supported by Capricornis crispus (Japanese serow) Public Health Service grant HD-03803 to F.H.B. Lived 52 from the National Institute of Child Health and 27 135 10.585 .002! + Human Development and by an NSF graduate Died 21 35 fellowship to AC. *For the sign test, + = juvenile mortality higher in inbred than noninbred young (P = .0003). tSignificant 30 January 1979; revised 11 May 1979 at .05 level; one degree of freedom in all cases; probabilities are rounded to three places. SCIENCE, VOL. 206, 30 NOVEMBER 1979 0036-8075/79/1130-1101$00.50/0 Copyright © 1979 AAAS 1101 Table 2. Breeding success of individual females which were mated to both unrelated and related was very high (elephant, Eld's deer, males. sable, and oryx). The increased mortali- Mating with Mating with ty rate of inbred young in the four spe- unrelated male related male cies with the largest sample sizes ranged Female Sign from a low of 28 percent in the Japanese Species Juvenile Juvenile (No.) Births Births test* deaths deaths serow to a high of 41 percent in the sita- (No.) (No.) (No.) (No.) tunga. Inbred young had a higher mortal- ity in 15 of 16 species (P = .0003, one- Pygmy hippopotamus 61 1 0 9 8 + 87 7 0 6 2 + tailed sign test), which suggests that in- 102 3 1 3 2 + creased juvenile mortality in inbred 112 10 3 1 1 + young is a general phenomenon in ungu- Muntjac 101,432 10 1 3 1 + lates and that the failure to show a sig- 34,847 8 0 2 0 0 nificant difference by the chi square test M00,510 1 1 4 2 - Eld's deer M00.391 1 0 2 2 + in some cases may be due to an in- M00.281 1 1 3 3 0 sufficient sample size per cell. In 19 of 25 Pere David's deer M00.346 1 0 3 1 + individual females, belonging to ten spe- Reindeer M00,029 2 0 3 2 + cies, a larger percentage of young died Oryx M00.262 4 0 1 1 + MO0,263 4 0 1 1 + when the female was mated to a related Wildebeest 28-375A 5 0 2 2 + male than when she was mated to an un- Dik-dik M00,540 4 1 1 1 + related male (Table 2) (P = .008, one- M00,901 1 0 1 1 + tailed sign test). Dorcas gazelle 28,147-B 10 5 3 1 - 28,918 8 0 11 6 + We have not yet analyzed most of our 30,168 5 3 6 5 + data with respect to the many other vari- Japanese serow TYM-1 9 1 2 0 - ables that might influence juvenile mor- KYT-7 6 2 1 1 + tality, such as birth season, management JSC-2a 2 1 4 4 + improvements, birth order of the young, JSC-2d 1 1 2 2 0 OMC-12 6 2 1 1 + and possible differences between wild- KOB-lcc 2 0 2 1 + and captive-born females.