Intraperitoneal transmitters in suckling white-footed mice, Peromyscus leucopus.

Intraperitoneal transmitter implantation in suckling white-footed mice, Peromyscus leucopus, was studied. Postnatal morphological development varied. Age ranged from 9 to 16 days, and body weight ranged from 4.4 to 7.3 g. Interference by mothers prevented successful implantation on sucklings which retained their neonatal appearance. Growth was measured in 6 sucklings for 21 days. Observed growth rates based on daily weight gain per 24 h were 0.29 and 0.32 g for implanted and control mice, respectively. Transmitter implantation resulted in a significant short-term weight loss (mean = 0.56 g) which was recouped prior to weaning. There was no evidence of impaired coordination or locomotor disability. This study concluded that intraperitoneal implantation is possible in suckling P. leucopus if surgery is delayed until venter pelage has developed sufficiently and eyes have been open at least 2 days. A few implications of using this technique to radio track small mammals are suggested.