Integration of metabolism and digestion in the hyrax

Abstract

Metabolic adaptations and digestive ability were integrated to explain the ecological efficiency of the hyrax (Procavia capensis). Metabolic rate was shown to decrease linearly with a drop in ambient temperature, but at a lower rate than an animal of equivalent size, the guinea-pig (Cavia porcel/us). This is achieved by lowering the body temperature with a drop in ambient temperature. Maintenance energy requirements within the thermoneutral zone are ca 700 kJ/day for mature and 400 kJ/day for immature hyrax and were supplied even on a poor quality laboratory diet. These factors explain the wide adaptability and competitive ability of the hyrax where its predators have been eliminated.

Metaboliese aanpassings en verteringsvermoe is ge"integreer ten einde die ekologiese effektiwiteit van die dassie (Procavia capensis) te verklaar. Die tempo van metabolisme het linier toegeneem met 'n verlaging in omgewingstemperatuur, maar teen 'n laer tempo as vir 'n dier van dieselfde grootte, die marmot (Cavia porcel/us). Dit is moontlik deur die Iiggaamstemperatuur te verlaag wanneer die omgewingstemperatuur verlaag. Onderhoudsenergie vereistes binne die termoneutrale gebied is ca. 700 kJ/dag vir volwasse en 400 kJ/dag vir onvolwasse dassies en is aan voldoen, selfs op 'n lae gehalte laboratoriumrantsoen. Hierdie faktore verklaar die wye aanpasbaarheid en die vermoe van die dassie om mee te ding waar sy roofvyande reeds uitgewis is.

Keywords: Hyrax, temperature-regulation, digestion, metabolic rate, conservation of energy