The sight of a fin in the ocean may be, depending on people, a trigger of uncontrollable fear or immense joy. I fall into the second category, mostly when it's a dolphin's fin.
Here are some facts to better know this species, common in South Florida waters:
Bottle nose dolphins are dark gray marine mammals, sometimes even black, with light gray on the flanks. Their belly is white with sometimes a slight pinkish color.
These animals measure 3 to 4 feet at birth for a weight between 30 and 40 pounds. Adults range from 8 to 12 feet and can weigh up to 1000 pounds.
Tursiops truncatus lives in a structured society segmented into four distinct age classes: newborns, juveniles, sub-adults and adults. Each of these classes corresponds to a particular period in the life of the individual to which physical characteristics and particular behaviors are associated.
The newborns are very pale in color, with a body marked by folds and fetal lines. The dorsal fin has no notches or scratches. There are also hairs around his rostrum during the first days of the animal. During the first 10 weeks, the mother stays very close and the body contact with the newborn is very important. There are many games and social behaviors during this period.
The age range of juveniles is between 10 weeks and 4 years. The juvenile dolphin is smaller than adults and sub-adults and its skin is paler. His behavior is similar to that of newborns with a lot of social activities and games. Juveniles are closely associated with their mothers or other youngsters in the group.
The age group of sub-adults concerns animals aged 4 to 14 years. Separation with the mother characterizes this period. They are sexually immature, the size is close of adults but the body is less robust. The dorsal fin is not yet marked or is less marked than adults. Sub-adults associate with each other primarily.
The adult Bottlenose dolphin is a dark-colored animal whose dorsal fin is marked with scratches and notches. Adults are usually accompanied by younger individuals or other adult.
Like all marine mammals, the Bottlenose dolphin is protected by several international conventions.
Tursiops truncatus is classified as a "minor concern" on the 2013 IUCN Red List (International Union for Conservation of Nature), which is not in decline despite the many threats to this animal and its habitat.