||What is the Difference
Between a Dolphin and a Porpoise?
27 August 1997
Dolphins and porpoises are so similar that it is
easy to confuse which is which.
In general, porpoises are smaller and plumper than
dolphins, rarely reaching lengths of more than 6
feet and weights of more than 300 pounds. They have
a rounded head and a small, triangular dorsal fin.
Porpoises lack the "beak" characteristic
of most dolphins, having a blunt snout instead.
is the most frequently spotted dolphin species in
North Carolina's coastal waters.
Most species of dolphins have long, streamlined bodies,
with a distinct pointed beak and a prominent dorsal fin
with a curvature toward the tail. Their size varies from
4-26 feet with weights ranging from 70-1,500 pounds. Their
teeth are sharp and cone-like in shape, in contrast to the
spade-shaped, laterally-compressed teeth of the porpoise.
The bottlenose dolphin is the species of toothed whales
most frequently spotted off the North Carolina coast. They
are typically inshore species, and most often are observed
in groups of about a dozen. Atlantic bottlenose dolphins
are robust, though streamlined, growing to lengths of
8-11 feet with weights ranging from 500-1,000 pounds. They
usually have light colored bellies and dark backs - colors
that help them blend in with their surroundings. Their lower
jaw projects beyond the upper, giving them the appearance
of wearing a permanent grin. The bottlenose dolphin is a
powerful swimmer that can often be spotted frolicking in
the bow wave of a vessel or surfing on large waves.
While some confusion may exist about the differences between
porpoises and dolphins, one thing is clear. Their numbers
are dwindling due to direct hunting, accidental catches
in nets of commercial fishing operations, and higher pollution
levels in the earth's oceans and rivers. The Marine Mammal
Protection Act, federal legislation enacted in 1972, protects
porpoises, dolphins, and all marine mammals in U.S. waters.