Earthwatch - Wild Dolphin Societies Teachers in the Field

Still more terrific questions (submitted by students at Quidnessett Elementary School, North Kingstown, RI)

How can you tell the difference between a boy and a girl dolphin?
From the boat you can see moms with their calves as a group, "subadults" hanging out together, and male pairs that swim together.  You can't really tell them apart physically from the boat but you can observe their behavior and if a mom is with her calf, then she is a female dolphin.
You would have to examine the dolphin closely on its belly directly opposite the dorsal fin to actually see its reproductive organs.

Why do whales beach themselves?
It is called "stranding." According to the Eyewitness book, Whales and dolphins, it is one of the great mysteries of the animal kingdom. There are several possible causes for live strandings. One theory is that the animal loses its sense of direction, perhaps because of changes in earth's magnetic field. Other theories are that an earthquake or storm causes panic, or a brain infection causes disorientation, or it may simply get lost or feel sick and its sonar system may fail.

Do whales and dolphins travel in the same pods?
No, but they are sometimes found in association. That means nearby each other.

Where do killer whales get their food?
In the waters that they frequent.

How many dolphins have you seen altogether?
Today we saw a group of 10 dophins, but once we saw a group of 14. I don't have a total yet but I will at the end of the week.

How far out can a dolphin swim in the ocean?
Dolphins are strong swimmers but they usually have a familiar area that they call their home region. Pelagic dolphins are ocean dwellers and are on the move. The bottlenose dolphins of Sarasota Bay are inshore, coastal dolphins.

What is the smallest type of dolphin?
New Zealand is home to the world's smallest and rarest dolphin, the North Island Hector's Dolphin. There are only thought to be about 100 left. They are critically endangered.

Why do dolphins live so long?
Their main predators are certain large sharks and killer whales, but mostly humans are affecting their longevity with pollution, heavy boat traffic, and habitat distruction.

A honeybee has two stomachs, a dinosaur has two brains. Anything unusual with the dolphins?
I think their melon and their echolocation ability is quite unusual.

How old is the oldest dolphin you have seen?
I don't know, but I'll ask tomorrow. I'll have to ask about who among the Sarasota dolphins is the oldest?

How large are their eyes?
I don't know. They don't look big in proportion to the body.

What is their average tooth size?
It looks from eyewitness books that a tooth is about an inch high. There is about 40 to 52 teeth in the upper jaw and 36 to 48 teeth in the lower jaw. Another interesting fact is that scientists will remove one tooth from the bottlenose in order to figure out its age. Like the rings in a tree trunk, the dolphin's tooth also has rings!

How big is the largest melon?
I don't know. Probably in proportion to the biggest dolphin!

Do you always tell the difference of the dolphins by their fins?
We did. Yes.

Do sharks eat dolphins?
Yes. Sharks are dolphins' chief predator in the natural world.

Have you swam with the dolphins?
No.

What is the record for the fastest dolphin swimming?
The U.S. Navy clocked a dolphin at 50 mph!

Was it very exciting when you saw the flamingo?
I wouldn't call it exciting but it is definitely a great story, and it's true.

What was the longest time a dolphin can stay underwater?
Dolphins average 3-4 minutes underwater, but once the Navy clocked a dolphin who stayed under for 7 minutes.

Do you think more flamingos will come to the bay?
I doubt it.

How long is a Pygmy Sperm Whale?
Newborn 4 ft.
Adult 9-11 1/4 ft

How long is the bottlenose dolphin?
Newborn 34 in. - 4 1/4 ft
Adult 6 1/4 - 12 1/4 ft

How long is the dorsal fin?
I don't know. Maybe a foot or more.

Have you ever seen a dolphin and a whale swim together? No

How do sharks communicate?
I have no idea. I wonder if they do.

How high do dolphins jump?
Trained dolphins can leap up to 10 feet, maybe more.

Is there albino bottlenose dolphins?
I don't know.

What is the temperature today?
about 80 degrees :-)

Were dolphins ever land animals?
This is a very good question. It is believed that dolphins and whales were land mammals and returned to the sea. they probably were furry land mammals that lived in coastal swamps and shallow seas. They had torpedo shaped bodies and their forelimbs (arms) became paddles. This all happened around 50 million years ago!
 
 
 

RESOURCES

Ellis, Richard. Dolphins and Porpoises. Alfred Knopf, New York 1989.
Cowardine, Mark. Whales, Dolphins and Porpoises. Eyewitness Handbook, DK Publishing, Inc. 1995.