Barbara J. Weir

The management and breeding of some more hystricomorph rodents

The caging, feeding and handling in our laboratory of 4 unusual hystricomorph rodents are described. These animals are: the wild guinea-pigs, or cuis (Cavia aperea and Galea musteloides), the degu (Octodon degus), and the plains viscacha (Lagostomus maximus). The species were obtained for investigation of their reproduction and some details of this are given.

The care and management of laboratory hystricomorph rodents

Summary The caging, feeding and handling of four unusual laboratory hystricomorph rodents is described. These rodents are: the chinchilla (Chinchilla laniger), the agouti (Dasyprocta aguti), the acouchi (Myoprocta pratti), and the African porcupine (Hystrix cristatd). The animals were kept for study of their reproduction and some details of this are given.

Genetic variation of phosphoglucose isomerase in some hystricomorph rodents.

Phosphoglucose isomerase electrophoretic variation has been studied in hystricomorph rodents. Intraspecies variation was found in chinchilla (Chinchilla laniger) and cuis (Galea musteloides). Interspecies hybridization of Cavia aperea and Cavia porcellus was found to produce hybrid enzymes. In all cases, breeding data indicated an autosomal mode of inheritance, while electrophoretic patterns were consistent with a dimeric structure for the enzyme. Possible evolutionary relationships of phosphoglucose isomerase with respect to taxonomy are discussed.

Another hystricomorph rodent: keeping casiragua (Proechimys guairae) in captivity

Caging, feeding and handling are described. The animals were obtained for study of their reproduction and details of this are given.

The Chromosomes of some octodontids with special reference to Octodontomys (Rodentia; Hystricomorpha)

The chromosomes of three species (Octodontomys gliroides, Octodon degus and Ctenomys talarum) of octodontid hystricomorph rodents are compared. — The diploid numbers are 38, 58 and 48 respectively. No polymorphic chromosomes were noted in the specimens available. The sex chromosomes are heteromorphic and pair end to end in meiosis. — The karyotypes are compared on the basis of the extreme specialisation of the habitat of the three species. The asymmetric karyotype of Octodontomys can be compared more readily with that of a Ctenomys ancestor than with that of its present-day relative, Octodon.

Urine composition of some hystricomorph rodents confined to metabolism cages

Abstract 1. 1. A comparison was made of the composition of urine from six species of hystricomorphs (chinchilla, plains viscacha, degu, cuis, native guinea-pig and domestic guinea-pig) maintained under laboratory conditions. 2. 2. All species produced moderate amounts of hypertonic urine and daily rhythms in water and electrolyte excretion were found. 3. 3. Potassium was the major inorganic ion, but a marked difference in renal magnesium retention was found in chinchilla (low) and degu (high). 4. 4. The preliminary results suggest that the control of electrolyte balance differs widely in the different species and that special mechanisms may exist in hystricomorphs for regulation of potassium and magnesium.