| dc.description.abstract | 1. The feeding rate of a whale is defined as the weight of daily food
ingested expressed as percentage of body weight. Records of daily
rations of Delphinoidea (porpoises and dolphins) in captivity allow
calculation of feeding rates for eight genera having adult body weights
of 10 to 10³ kg.
2. There is an inverse relation between feeding rate and body weight,
both between species and between young and adult Delphinoidea. The
range of feeding rates is from 12-13% to 4-6%. Above a body weight
of 6x10² kg, represented by adult Tursiops truncatus, feeding rate remains
constant at 4-6% up to the largest species in which it has been
measured, the killer whale, Orcinus, of body weight 2 x 10³ kg.
3. Heart weight expressed as proportion of body weight varies directly
with feeding rate and is equal to about one tenth of it. Young animals
of all species, as well as adults of Phocoenoides dalli and possibly Phocoena
phocoena have high feeding rates and heart weights, showing that both
indices measure metabolic rate. From their heart weight/body weight
ratio an attempt has been made to calculate feeding rates of whales too
large to be kept in aquaria.
4. Heart weight/body weight ratios of adults rorquals of the genus
Balaenoptera are about 4‰; of sperm whales, Physeter and one example
of the small, related Kogia, lowest of all at 3.5‰,. These data suggest
a feeding rate of 4% for adult rorquals, so that from curves relating body
length and body weight, their daily food consumption may be calculated. | |
