Many do not know that dolphins are mammals just like us. Even though their body shape reminds us of fish, they have kept characteristic of a mammal; they are warm-blooded, they breathe with lungs and their cubs are fed with mother’s milk.
Bottlenose dolphins are world inhabitants, while currently in Mediterranean there are less then 10.000, while in Adriatic about 250 individuals; which number is being reduced by overfishing, habitat destruction and pollution. Also, the number of cubs are limited in an average dolphin’s life. Because of, its scarce natality, they are not able to grow in population.
Since they live in different environments, all over the world, they are very distinctive in they appearance. Therefore, the largest dolphins can be 4 meters long and weight up to 500 kilograms. The ones living in deeper seas (ocean type) are larger and heavier, while ones in shallow waters (coastal eco –type), like ones in Croatia, can reach maximum adult size of 3 meters.
Bottlenose dolphins feed on fish, squids and crustacea (crabs, lobsters, shrimps…). Since they air breathe, they have to surface every 4 to 5 minutes. If in danger, the adult dolphin can spend 6 to 7 minutes underneath the surface. They approximately dive between 30 to 70 meters; however, they can go deep up to 300.
Bottlenose dolphins can live up to 50 years, although its average life span is 30 years. They sexually mature when about 10 years old. Bottlenose dolphins do not raise their cubs as a couple. They are very promiscuous and they are often involved in sexual activities. They mate in spring and early summer, since the water temperature at this period will keep they cubs warm while growing their fat coat. They have babies every 3 to 5 years, carrying them for 12 months.
When a new born catches his first breath on the surface his mother is constantly releasing a signature sound that is recognized as a dolphin’s name. The baby dolphins are not able to suckle, and therefore the mother is feeding its cub by suppressing the mammary glands to the cub’s mouth. In order to avoid blending milk and seawater the milk produced by dolphins is thick and fatty with about 14% of milk fat, which has 4 times more fat than in regular cow milk.
The cub spends 3 to 5 five years with his mother learning from her and becoming an in depended dolphin. Afterwards, it joins a “teenage” group, that we often see fooling around when they willingly approach boats surfing on their waves.
The small visibility in the sea made dolphins develop echolocation – a system of communication that enables dolphins to crate a picture of the environment they are currently in, by producing high frequency sounds. It is considered that using these sounds dolphins can stun their prey. Except the sound, dolphins use their eyes that are equally efficient under and above the sea.
Bottlenose dolphins use different hunting techniques developed within the groups they live in. Almost every population has their own special hunting techniques depending on environment surrounding them. For example, some of them hunt in bigger groups to disenable their prey to escape, while others are specialized for hunting fish that bury in sand. Some of them hunt in collaboration with fisherman, while others are specialized in stealing from them.
Dolphins are intelligent species and therefore the humans always felt sympathy and connection with them. Numerous legends in the world are witnessing their appreciation within different cultures where they even embodied Gods. Some legends say that they were saving drowning man and sailors, as well as helping human souls transcend in the world of death.
No matter what you believe in, there is a certain bond between human and dolphins, and therefore, appreciate it, since they are not endangered by any species in the food chain, but human.
Source: Plavi Svijet