They are known worldwide for their ability to do tricks like using tools and doing mimicry, thanks to their participation in aquarium shows. For communication, bottlenose dolphins use various sounds and movements like squeaking, whistling and sometimes, leaping high into the air and splashing down with their tails while coming back.
In one second, they can produce up to 1, clicking sounds. Bottlenose dolphins appearance is quite well known due to their curved mouths that give them the smiling look. Bottlenose dolphins are dark-gray to bluish-gray on top and pale-gray to white from the underside.
Echolocation tells the dolphins the shape, size, speed, distance, and location of the object. Bottlenose dolphins have a sharp sense of hearing. Scientists believe that the sounds travel through the dolphin's lower jaw to its inner ear and then are transmitted to the brain for analysis. Dolphins grow to be anywhere from 6 to 12 feet long. They shed their outermost layer of skin every two hours. Very social and playful mammals , bottlenose dolphins form friendships that last decades hunting, mating and protecting each other.
They like to surf in the waves and wakes of boats and swim through self-made bubble rings. They can swim up to 22 miles an hour. These sea mammals feed on fish , squid , and shrimp. A group of dolphins will cooperate to make a mud ring to trap fish. Then, some of the dolphins in the group will wait outside the ring for the fish that try to escape, gulping them up as a snack. Bottlenose dolphins are found in warm water all over the world. They live both in shallow water close to shore and far out in deep dark water.
NOAA Fisheries helps conserve bottlenose dolphins through collaborative management, integrated science, partnerships, and outreach. Our scientists use a variety of innovative techniques to study, protect, and rescue bottlenose dolphins in distress e. We facilitate collaborative approaches to better understand and reduce harmful effects of human activities on bottlenose dolphins and their habitat based on sound science, conservation, public input, and public outreach.
Like all marine mammals, bottlenose dolphins are protected under the MMPA. In all, 61 stocks of common bottlenose dolphins have been identified in U.
Population trends for many of the U. Common bottlenose dolphins get their name from their short, thick snout or rostrum. They are generally gray in color. They can range from light gray to almost black on top near their dorsal fin and light gray to almost white on their belly. Bottlenose dolphins living in nearshore coastal waters are often smaller and lighter in color than those living offshore.
Bottlenose dolphins may travel alone or in groups, and the groups often break apart and reform. Their travel is characterized by persistent movement in a consistent direction. Resting is often characterized by tight group formations, slow movement, and intervals of methodical breathing.
Social behavior includes breeding, playing, aggression, and gentle body contact, such as rubbing. When in baby position, the mom surfaces first, and the calf surfaces slightly after and just behind and to the side of its mother. Bottlenose dolphins can thrive in many environments and feed on a variety of prey, such as fish, squid, and crustaceans e. They use different techniques to pursue and capture prey, searching for food individually or cooperatively. For example, they work together to herd fish into groups and then take turns charging through the school of fish to feed.
They may also trap schools of fish against sand bars and seawalls for an easy meal. Instead of using their teeth to chew, dolphins grip fish with their teeth, then swallow the fish whole—head first—so the spines of the fish don't catch in their throats.
Bottlenose dolphins are found in temperate and tropical waters around the world. They inhabit a wide variety of habitats, including harbors, bays, gulfs, and estuaries, as well as nearshore coastal waters, deeper waters over the continental shelf, and even far offshore in the open ocean. Bottlenose dolphins can live at least 40 years, with some females outliving males at 60 years or more. They generally begin to reproduce when they are between 5 and 15 years old, with the exact age varying by population.
Female bottlenose dolphins can reach sexual maturity before males. Females are pregnant for about 12 months and give birth, on average, every 3 to 6 years. Once calves are born, they nurse for 20 months or so and generally stay with their mothers for 3 to 6 years. Females as old as 45 have given birth. Bottlenose dolphins are exposed to a variety of human-caused and natural threats and stressors.
Some of the most pressing threats are discussed below. One of the main threats to bottlenose dolphins is getting caught in fishing gear.
Dolphins can become entangled or captured in commercial fishing gear such as gillnets, seines, trawls, trap pots, and longlines. In addition to interactions with commercial fisheries, dolphins may become entangled in or ingest rod-and-reel gear used by recreational anglers or for-hire fishing vessels, such as charter boats and headboats, which can lead to serious injury or mortality.
This problem is increasing, especially in the southeast United States and is largely the result of dolphins taking the bait and the catch directly from fishing gear, eating discarded fish, or being fed fish illegally by humans, causing them to associate anglers with food. In addition, fishermen sometimes become frustrated when dolphins take their catch and can retaliate with violence towards dolphins. Common bottlenose dolphins living near shore are also susceptible to habitat destruction and degradation by contaminants and oil spills.
For example, in areas with high levels of polychlorinated biphenyls PCBs dolphin immune systems can be negatively affected. Dolphins in areas affected by the Deepwater Horizon oil spill were found to have compromised immune systems and decreased reproductive success PDF, pages.
In addition to chemical contamination, physical habitat alteration due to shoreline development and infrastructure projects, freshwater diversions, and increased boat traffic is also of concern. Several common bottlenose unusual mortality events UMEs have occurred in recent years, linked to harmful algal blooms HABs , such as red tide. Dolphins can be exposed to HAB toxins through the air or by eating contaminated prey. Biotoxin exposure can lead to both acute and more chronic health issues for dolphins.
Bottlenose dolphins are easy to view in the wild, but this also puts them at increased risk of human-related injuries and death. Feeding and attempting to feed dolphins is not only illegal under the implementing regulations of the MMPA but is harmful because it changes their behaviors and reduces their wariness of people and vessels.
Dolphins, including calves, also learn these unnatural and risky feeding strategies from each other. Dolphins are then more vulnerable to vessel strikes and to fishing gear entanglements and ingestion.
They also may fall victim to extreme retaliatory acts, such as shooting, by frustrated boaters and fishermen. Dolphins may also be disturbed or harassed by the presence of humans and watercraft.
Certain critical survival behaviors are particularly vulnerable, and disturbance may lead to injuries or death. Long-term negative effects may include compromised health, reduced reproductive success, and displacement from or avoidance of important habitats. All bottlenose dolphins are protected under the Marine Mammal Protection Act. Some specific stocks in need of additional protections are designated as depleted or strategic. Our work supports the protection and conservation of bottlenose dolphins by:.
NOAA Fisheries conducts research on the biology, behavior, and ecology of bottlenose dolphins to better inform management and policy. Examples include:.
Serious and sometimes fatal dolphin injuries are on the rise from interactions with rod-and-reel fishing gear and boats. Here are some tips to prevent injuries to dolphins:.
Never feed or attempt to feed wild dolphins or throw trash in the water.
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