Scientists have observed a dolphin mum adopt and care for a whale calf.
It is the first known case of this happening.
The researchers saw an adult female bottlenose dolphin caring for an unusual-looking male calf in water off the islands of French Polynesia in the South Pacific Ocean.
The mum also had a more regular-looking female calf.
Bottlenose dolphins have slim beaks. The odd, one-month-old male calf had a short, blunt beak nothing like all the dolphins around him.
Eventually, the researchers realised that the male calf was not a dolphin but a melon-headed whale, which is a different species.
The researchers’ results are published in the journal Ethology and were reported on by National Geographic.
Dolphin adopts whale calf
To this point, the dolphin story was just like the Hans Christian Anderson story “The Ugly Duckling”, about the plain-looking bird that gets teased because he doesn’t look as cute as his brothers and sisters.
In the fairytale, it turns out the ugly duckling wasn’t a duckling at all, but a baby swan who grew up to be the most beautiful of them all.
The real-life story of the ugly dolphin is much nicer than the fairytale.
The study of 30 bottlenose dolphins began in 2009, with the researchers watching the male calf for three years from 2014.
They saw he fitted in beautifully with the female calf and played with all the other dolphins in the area as though he was a dolphin.
Pamela Carzon led the study as part of a research group called GEMM (Groupe d’Étude des Mammifères Marins de Polynésie), based in Tiputa, French Polynesia.
“The melon-headed whale was behaving exactly the same way as bottlenose dolphins,” Ms Carzon told National Geographic.
He often joined all the others surfing and playing in the waves.
They didn’t see anyone ignore him or try to get him to go away even though he looked quite different.
The mother was also completely devoted*. The little family of three were often seen swimming together, which in itself was surprising as dolphins almost always only care for one calf at a time. The mother also breastfed both the male and female calves.
The female calf disappeared for an unknown reason after about one-and-a-half years but the male calf stayed with the mother for three years, until the time a calf would normally leave its mother.
It is not known why the dolphin mother adopted the whale calf. Suggestions include luck, a tolerant* mum and a determined whale calf.
HOW DOLPHINS FEED THEIR CALVES
Mammals feed their young on milk the mother produces in special glands on the abdomen* called mammary glands or breasts.
Like other mammals, female dolphins feed their calves milk, usually for at least the first year of the calf’s life.
Most land mammals have breasts that protrude (stick out) from their abdomens and the baby puts its mouth over the teat and sucks to get milk.
Dolphins’ mammary glands are inverted, which means they are an inside-out shape. When the calf wants to feed it pushes its beak or nose into one of two slits in the mother dolphin’s belly and forms a seal in the inverted teat before the mother releases milk.
ANOTHER SPECIAL ADOPTION
Scientists have only once before observed a wild mammal adopt an orphan of another species.
In 2006, primatologist* Pactricia Izar from the University of Sao Paulo saw a group of capuchins — a small monkey — caring for a baby marmoset, which is a different species of small monkey.
Wild mammals don’t usually adopt another baby. If they do, the young mammal is most likely to be related to them and the same species.
- devoted: committed
- tolerant: able to put up with something annoying
- abdomen: body including chest and belly
- primatologist: a scientist who studies primates
- How did the whale calf look different from the bottlenose dolphins?
- Where in the world did these dolphins and the whale calf live?
- Do we know why the dolphin adopted the whale calf? What are the possible reasons?
- What is different about how a dolphin calf breastfeeds compared to most land mammals?
- Is it common for wild mammals to adopt babies of other species?
LISTEN TO THIS STORY
1. Compare and contrast
Sketch a picture of a bottlenose dolphin and a melon-headed whale. Create a Venn diagram to go with your pictures, comparing and contrasting the two species. You should include at least 3 traits they share and 3 traits that are unique to each one.
This activity will require further research.
Time: allow 30 minutes to complete this activity
Curriculum Links: English, Science, Visual Art
This is the type of story that could be adapted to make a super cute movie!
Imagine you are a movie executive. Think of a great name and tagline for the movie. (A tagline is a short phrase or sentence that is often displayed on movie posters that gives a little more information about the movie. Examples — The Lego Movie Part 2: They Come in Pieces; Finding Dory: An unforgettable journey she probably won’t remember; Show Dogs: Unleashed and Undercover; etc.)
Now come up with an idea for a happy ending to the movie. Write down a brief outline of your ending.
Time: allow 10 minutes to complete this activity
Curriculum Links: English
With a partner see if you can identify all the doing words/verbs in this text. Highlight them in yellow and then make a list of them all down your page. Now see if you and your partner can come up with a synonym for the chosen verb. Make sure it still makes sense in the context it was taken from.
Try to replace some of the original verbs with your synonyms and discuss if any are better and why.
HAVE YOUR SAY: What wild animal species would you like to film and study if you were a scientist?
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.