Phocoena dalli - Porpoid

PHOCOENOIDES DALLI

Note 1

SCIENTIFIC CLASSIFICATION

Kingdom

Animalia

Phylum

Chordata

Subphylum

Vertebrata

Class

Mammalia

Order

Cetacea

Suborder

Odontoceti

Family

Phocoenidae

Kind

Phocoenoides

Species

Phocoenoides dalli

subspecies

Phocoenoides dalli dalli

subspecies

Phocoenoides dalli truei

Common name

GENERAL DATA

• Body length : 1.80 - 2.20 m
• Weight: 130 - 220 kg
• Lifespan: 16 - 17 years
• Sexual maturity: female 3 - 6 years; male 5 - 8 years

HABITAT AND GEOGRAPHICAL DISTRIBUTION

There Phocoenoides dalli belonging to the family of Phocoenidae and known simply as porpoise, it includes cetaceans that live in the northern part of the Pacific Ocean and adjacent seas. The northern limit is the Bering Sea. They are found, especially during the winter months in the Gulf of California (Mexico) and also along the coasts of Japan.

They are creatures that mostly live in cold, deep waters, so much so that it is thought that when they approach the coast they do so exclusively because they follow underwater gullies.

PHYSICAL CHARACTERISTICS

Among all the members of the family Phocoenidae, the porpoises are the largest, reaching 2.20 m in length and a weight of 220 kg. This greater bulk gives these porpoises greater physical strength.

Note 1

As for the color of the coat, different shades were observed: all white or all black; black and white stripes running along the entire body; the dorsal part all black with large white lateral and ventral patches (the most common type).

They too, like all members of the family, have a small head without the rostrum typical of dolphins and with a sloping forehead.

The pectoral fins are very small in proportion to the body and far forward, near the head; the dorsal fin is the typical one of the family, triangular in shape, while the caudal fin is large and robust which allows it to reach speeds of 35 km / h.

It is thought that they are cetaceans that are able to go very deep as fish that live in the sea depths have been found in their stomachs.

CHARACTER, BEHAVIOR AND SOCIAL LIFE

They are not animals that live in large groups, at most in groups of 10-20 individuals even if much larger aggregations have occasionally been observed.

Sometimes groups formed by the Phocoenoides dalli, from Phocoena phocoena and the gray whale, especially in areas of Alaska.

They are migratory animals that head south in winter.

Compared to other porpoises, they are particular in that they do not have the reserved and shy character typical of the members of this family.

Note 2

They are seen jumping out of the water and zigzagging very quickly. As you can see from the image on the side, these porpoises when they swim are so fast that they create fan-like sprays called "rooster's tail" as they resemble the tail of a rooster and this represents a distinctive character for their recognition when they are seen. whiz on the open sea.

COMMUNICATION AND PERCEPTION

Porpoids use echolocation (a sonar-like system in the head) to both navigate and capture prey. It is thought that it can also be used for interspecies communication. They are animals that make a wide variety of sounds including clicks, screeches, whistles.

EATING HABITS

The diet of the porpoises consists of squid, hake, mackerel, herring, sardines and crustaceans. They feed mainly at night.

REPRODUCTION AND GROWTH OF THE SMALL

The mating systems and reproductive biology of the Phocoenoides dalli. From the few observations carried out, it has been deduced that generally they do not reproduce every year but every 3-4 years, this probably due to the fact that the breastfeeding of the young lasts about two years. The gestation should last about 11 months, at the end of which only one small about 0.80 - 1.2 m long is born.

Males do not contribute to the care of the offspring.

PREDATION

The main predators are leorcas (except for man).

STATE OF THE POPULATION

There Phocoenoides dalli it is classified in the IUNC Red list (2009.1) among animals at low risk of extinction in the wild LEAST CONCERN (LC) as it is estimated more than one million specimens worldwide.

Thousands of specimens are killed every year by the Japanese and the Russians both because they are actively hunted and because they get entangled in fishing nets.

SOCIAL, ECONOMIC AND ECOSYSTEM IMPORTANCE

These cetaceans are important predators of cephalopods and fish in general.

They are very important in ecotourism as being very sociable and playful animals, they interact very well with humans.

CURIOSITY'

There Phocoenoides dalli it owes its name to William H. Dall, an American zoologist who was one of the first to identify the species.

Note

(1) Image taken from Wild Whales b.c. cetacean sightings network
(2) Non-copyrighted image: Courtesy Photo NOAA - Alaska Fisheries Science Center