Curious about the dolphins you’ll see on our Hilton Head dolphin cruise? Learn the answers to frequently asked questions about our most playful residents!

How do dolphins sleep?

Dolphins have to be conscious to breath, this means that they cannot go into a full deep sleep, because then they would suffocate. Dolphins have “solved” that by letting one half of their brain sleep at a time. This has been determined by doing EEG studies on dolphins. Dolphins sleep about 8 hours day in this fashion. REM (Rapid Eye Movement) sleep, usually associated with dreaming has been recorded only very rarely. Some scientists claim dolphins do not have REM sleep at all.

How intelligent are dolphins?

The short answer to this is that we do not know. There is no reliable method to measure intelligence in humans across cultures, so it is not surprising that comparing humans, dolphins, apes, dogs, etc. is impossible. There are some indications of their potential: they are fast learners and can generalize. Also they can learn to understand complicated language-like commands.

How do dolphins communicate; do they have their own language?

Dolphins communicate mainly by means of sounds. These sounds include whistles, but also so-called pulsed sounds, which are often described as squawks, barks, rasps, etc. But they also use breaching (jumping and falling back into the water with a loud splash) and pectoral fin (or flipper) and tail (or fluke) slaps (hitting the flipper or fluke on the water surface). Body posturing and jaw popping also have a role in communication. This list is not exhaustive.

How does dolphin sonar work?

Dolphins (and other toothed whales) can produce high-pitched clicks. When these clicks hit an object, some of the sound will echo back to the “sender”. By listening to the echo and interpreting the time it took before the echo came back, the dolphin estimate the distance of the object.

If the object is a fish, some sound will reflect off the skin on the dolphin’s side, some of the bones, the internal organs and the skin on the other side. So one click can result in a number of (weaker) echoes. This will give the dolphin some information about the structure and size of the fish. By moving its head (thereby aiming the clicks at other parts of the fish) the dolphin can get more information on other parts of the fish.

For technical information on dolphin sonar, check out the following book: W.W.L.Au (1993) The sonar of dolphins. (Springer-Verlag New York).

Can dolphins combine information from their sonar with their vision?

The short answer is: yes, they can. Just like people can visualize an object by just touching it, dolphins can get an idea of what an object looks like by scanning it with their sonar. They can also identify objects with their sonar that they have only been able to see.

What and how much do dolphins eat?

Bottlenose dolphins eat several kinds of fish (including mullet, mackerel, herring, cod) and squid. The composition of the diet depends very much on what is available in the area they live in and also on the season.

The amount of fish they eat depends on the fish species they are feeding on: mackerel and herring have a very high fat content and consequently have a high caloric value, whereas squid has a very low caloric value, so to get the same energy intake (calories) they will need to eat much more if they feed on squid than if they feed on mackerel or herring.

On average an adult dolphin will eat 4-9% of its body weight in fish, so a 250 kg (550 lb) dolphin will eat 10-22.5 kg (22-50 lb) fish per day.

How old can they get?

The maximum age for bottlenose dolphins is between 40 and 50 years.

How did dolphins evolve?

The earliest recognizable cetaceans lived about 50 million years ago. These evolved from the Mesonychids: large land mammals, some of which were carnivorous, some herbivorous. The earliest cetaceans were members of the now extinct family Archaeoceti (the best known of which are Zeuglodon and Basilosaurus). 38-25 million years ago the Archaeoceti disappeared and were replaced by the early Odontocetes (toothed whales) and Mysticetes (baleen whales). The earliest dolphins appeared in the late Miocene period, some 11 million years ago.

The land animals that are closest to whales and dolphins are the Ungulates (hoofed animals). This was determined among others by comparing the structure of body proteins.

How can you interact with wild dolphins?

When swimming, boating or snorkeling in certain areas you can encounter wild dolphins. Keep in mind that in the US it is illegal to directly approach dolphins. If dolphins come towards you and choose to interact, that is allowed.

Why do whales and dolphins beach themselves?

If a single whale or dolphin strands, it usually is a very sick (and exhausted) animal. Such an animal often has some infections (pneumonia is almost always one of them) and a lot of parasites (worms in the nasal passages are very common). Sometimes these animals can be rehabilitated, but often they are so sick they won’t make it.

How deep can dolphins dive?

The deepest dive ever recorded for a bottlenose dolphin was a 300 meters (990 feet). This was accomplished by Tuffy, a dolphin trained by the US Navy. Most likely dolphins do not dive very deep, though. Many bottlenose dolphins live in fairly shallow water. In the Hilton Head area, the dolphins spend a considerable time in waters that are less than 2 meters (7 feet) deep.

How fast can dolphins swim?

The dolphin’s fast cruising speed (a traveling speed they can maintain for quite a while) is about 3-3.5 m/s (6-7 knots, 11 – 12.5 km/hr). They can reach speeds of up to 4.6 m/s (9.3 knots, 16.5 km/hr) while traveling in this fashion. When they move faster, they will start jumping clear of the water (porpoising). They are actually saving energy by jumping.

Where can you find dolphins?

Dolphins can be found in almost every sea and ocean, from the Arctic ocean, through the tropics all the way to the Antarctic. Each species however has its own preferred type of habitat. Some live cold water only, others in tropical oceans only.

How do dolphins get their water?

Most dolphins live in the ocean and the ocean water is too salty for them to drink. If they would drink sea water, they would actually use more water trying to get rid of the salt than they drank in the first place. Most of their water they get from their food (fish and squid). Also, when they metabolize (burn) their fat, water is released in the process. Their kidneys are also adapted to retaining as much water as possible. Although they live in water, they have live as desert animals, since they have no direct source of drinkable water.

We find dolphins absolutely fascinating. Seeing them one our charters one of the best parts of our time on the water. If you’re looking for the best things to do in Hilton Head, SC, you can’t miss out on a fun dolphin cruise! We can customize our boat tours for groups of 2-12 people. Contact us today to reserve your seat!