Mississippi State Water Mammal

Bottlenose Dolphin

(Tursiops truncatus)

Adopted on April 12, 1974.

The Bottlenosed Dolphin is the state water mammal for Mississippi.

An act designating the Bottlenosed Dolphin (Tursiops truncatus), commonly called the Porpoise, as the state water mammal was approved April 12, 1974, Chapter 551, General Laws of Mississippi of 1974.

The terms porpoise and dolphin are often used interchangeably. Usually, they refer to the bottle-nose dolphin (Tursiops truncates), the species commonly found along Florida's Atlantic and Gulf coasts. Dolphins are gray with a lighter underside. They can live to the age of thirty, occasionally attaining a length of twelve feet, although most are in the six- to eight-foot range.

Bottlenose dolphins are small, toothed whales that have a long, beaklike snout, a sickle-shaped dorsal fin, and sharp teeth. Dolphins breathe air through a single blowhole. They grow to be at most 12 feet (3.3 m) long. Dolphins live in small groups of up to 12 whales; these groups are called pods. Bottlenose dolphins have a life span of about 25 years.

Mississippi State Water Mammal:
Bottlenosed Dolphin

Bottlenose dolphins, the genus Tursiops, are the most common and well-known members of the family Delphinidae, the family of oceanic dolphin. Recent molecular studies show the genus contains two species, the common bottlenose dolphin (Tursiops truncatus) and the Indo-Pacific bottlenose dolphin (Tursiops aduncus), instead of one. Research in 2011 revealed a third species, the Burrunan dolphin (Tursiops australis). Bottlenose dolphins inhabit warm and temperate seas worldwide.

Characteristics of the Bottlenosed Dolphin

Adults range in size from 2.4 - 3.7 m (8 - 12 ft) in total length. Color: Light to purplish gray on upper parts of body. Sides pale gray, belly white. Other things to look for: Bottlenose Dolphins are probably the most familiar of all cetaceans to the general public, since most people have seen them on television programs and commercials, or at aquariums, zoos, and marine parks.

Life Cycle

Breeding activity peaks in March and April, and the gestation period is about 12 months. The single calf is born between the months of February and May. Its average weight at birth is 13.6 kg (30 lb.) and it is approximately 1.1 m (3.5 ft) in length. The calf is born tail first and swims immediately to the surface to breath. It will suckle for 18 months before it is weaned. A female Bottlenose Dolphin reaches sexual maturity at 6 years of age and then produces young every 2- 3 years. A male reaches sexual maturity by 10 years of age.

Natural History

The preferred habitat for this species is coastal shallow waters such as bays, estuaries, passes, and inlets, but it will also inhabit offshore waters within the 100 fathom (600 ft) depth line. The Bottlenose Dolphin feeds primarily on fish, but will also eat shrimp, crabs, and squid. It has been observed to herd fish into tight schools, which makes it easier to catch prey. It is also attracted to shrimp trawlers, where it feeds on fish attracted to the boat or the bycatch (unwanted fish, etc.) which is dumped over the side. The Bottlenose Dolphins is known for its ability to use echolocation not only to locate objects but also to discriminate between different sizes and shapes. A group or pod of Bottlenose Dolphins has a social hierarchy where males compete for dominance based on larger body size. Females do not engage in this social dominance behavior.

Mississippi Law

The law designating the bottlenosed dolphin as the official Mississippi state water mammal is found in the Mississippi Code, Title 3, Chapter 3. Section 19

Title 3 - STATE SOVEREIGNTY, JURISDICTION AND HOLIDAYS
Chapter 3 - STATE BOUNDARIES, HOLIDAYS, AND STATE EMBLEMS
§ 3-3-19 - State water mammal

Universal Citation: MS Code § 3-3-19 (2013)

The bottlenosed dolphin (Tursiops truncatus), commonly called the porpoise, is hereby designated the state water mammal of Mississippi.

Taxonomic Hierarchy: Bottlenosed Dolphin

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Delphinidae
Genus: Tursiops
Species: T. truncatus
    Subspecies: T.t.truncatus
    Subspecies: T.t.poncticus