Bottlenose Dolphins © Lisa Murpphy
Bottlenose Dolphins © Lisa Murpphy
DOLPHINS
The Atlantic Bottlenose Dolphin is the most common dolphin seen in our area. This playful and intelligent creature is the one most often seen at aquarium shows. Dolphins are small whales and belong to a group known as toothed whales. They have numerous conical canine-type teeth used for grabbing fish and squid. Dolphins cannot chew because they lack molars. They must select prey they can either cut into smaller pieces or swallow whole. Mammals as a group are known as heterodonts (meaning they have more than one type of tooth in their mouths). Humans have incisors, canines, pre-molars, and molars. Whales and dolphins break this rule by being homodonts (just one type).
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Bottlenose Dolphin
The toothed whales are known for their ability to detect prey using a form of SONAR called echolocation. Sound pulses are produced by flaps of skin within the blowhole (the nostrils of the dolphin) and exit the animal through a blob of fat in the head called the melon. Low frequency clicks can travel farther to find the target. High frequency clicks have shorter range but can tell the dolphin what type of fish it is. Some whales can even produce high enough frequencies to literally stun their prey in the water – making it easier to grab. These echoes or clicks are usually outside our hearing range.
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Bottlenose Dolphin © Lisa Murphy
Dolphins are very social animals that travel in large groups called pods. The pods are typically made of adult females and young, but may include one or two males. They communicate with each other using sound. The sounds are produced from the larynx in the blowhole area and are distinct for each pod. Outside dolphins are usually not allowed within the pod, so dolphins are not always the friendly creatures we perceive them to be – at least not to each other.
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Pod of Dolphins © Harry Purcell
The female dolphin gives birth to a single calf (twins occur rarely). She rolls while swimming forward to expel the young – who must quickly surface for its first breath. The other females in the pod usually help with this. The baby suckles milk from hidden mammary glands which the mom exposes when the calf nudges her side. The calves stay with their moms for about two years learning the tricks of the trade before the cycle begins again.
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