About the wisdom of children (part four)
by firmm Team
Text: Edeltraud Konradt; Photos: firmm
As every year at the end of the season, Edeltraud summarises the most interesting children's questions and answers them in detail.
Do dolphins also get sick?
Yes, they can get quite a few diseases.
Dolphins have physical similarities to humans, which is why marine mammals can also suffer from the same diseases.
Dolphinschutz.org. has listed a number of infection risks and dangers when swimming with dolphins and in dolphinariums.
The following bacteria were found:
Streptococci have been found, causing sore throats, scarlet fever and pneumonia, among other things.
- Staphylococci cause meningitis, pneumonia, kidney and wound infections, among others.
Pseudomonas are triggers of respiratory diseases such as Legionnaires' disease and chronic lung infection.
Aeromonas are bacteria that cause diarrhoea, wound infection and urinary tract infections.
- The bacterium Erysipelothrix in turn causes skin irritations, the bacterium Vibrio causes cholera, among other things.
Clostridia cause tetanus, among other things.
Mycobacteria are the cause of skin infections and tuberculosis.
These are joined by a number of viral infections such as smallpox, rabies and rotaviruses (the latter can cause diarrhoea and vomiting). Fungal diseases such as blastomycosis are also dangerous and can affect the lymph nodes and internal organs.
This list refers to dolphins in dolphinariums.
However, dolphins in the wild are also exposed to high risks of infection, e.g. by algal toxins, heavy metals (especially lead and mercury) or organ chlorins. These seawater pollutants come from huge rubbish carpets, as well as from pesticides, herbicides, artificial fertilisers, detergents, sewage and oils that flow into the sea. Other marine mammals such as seals, penguins and turtles also fall ill. Fish are also polluted. The entire food chain in the sea is affected by pollution.
In Eckernförde Bay, a dolphin was sighted in April 2020 with a fungal infection on its skin and coughing. The dolphin died at the end of January 2021. The autopsy report gave pneumonia as the cause, caused by lung worms. In addition to the pneumonia, he had severe stomach ulcers and a massive skin disease (smallpox). This weakened his immune system. Whether the stress to which the animal was exposed by too many visitors in the bay was also a trigger for the weakening of the immune system remains unexplained.
Parasitic lungworms are ingested by seals and dolphins with their food and then migrate into the lungs. There they can cause pneumonia if the infestation is severe, from which the marine mammal then dies.
- Type 2 diabetes: Dolphins can have too high a sugar level in their blood after eating, which, unlike in humans, lowers itself again.
- Kidney stones
- Lung diseases or lung worms
- Skin diseases: Fungal infections and inflamed wounds
I would like to end my list of diseases here, because the list could be much longer. I am shocked, I would not have thought that possible.
Why don't Orcas eat humans?
... After all, humans would be helpless in the water and thus easy prey.
Marine biologists say: Orcas are intelligent and curious. Maybe they recognise the difference between intelligent beings and their prey and that's why they don't attack us ...
Orcas fish with air bubbles.
Yes, that's right for small fish like herring. Catching individual fish is costly and not worth it, so the Orcas developed a strategy.
First, Orcas isolate part of a huge school of fish. They encircle it so that the fish can no longer escape. Some of them now dive under the isolated school of fish and let air bubbles rise to drive the fish to the water surface. Then they hit the water surface with their flukes. The fish are beaten to death or stunned. Now the meal is ready: the big feeding begins. This behaviour has been observed off Norway.
Orcas eat sharks
Although I answered YES to this statement from a young boy in my lecture, I must now correct it here.
The scientist Lauren Smith has observed that Orcas hunt white sharks and then eat the innards. The reason for this is that the liver of the sharks contains an oily substance. These are important nutrients for the animals.
What do whales and dolphins do with the bones and fish bones of their prey?
Well, they swallow them, because whales don't chew. Dolphins eat fish, the whole fish, it is swallowed whole and in the stomach the bones are decomposed by the stomach fluid. The non-digestible parts are excreted with the faeces. It is the same with large whales: the food is swallowed whole. If the prey of an Orca is a sea lion, for example, the prey is torn apart and swallowed in parts.
How do dolphins reproduce?
Also OK: Let´s talk about dolphin sex!
Dolphins are very tactile. They often like to touch each other with their front flippers. These are very sensitive. The touching strengthens the feeling of togetherness. The mating act itself only lasts a few seconds. Dolphins do it often and with changing partners, this is part of their social structure. Masturbation (rubbing and stimulating each other on the seabed) and same-sex stimulation, practice and trial and error have also been observed. Mutual stimulation happens via beak touch and very focused sounds on the other dolphin's genital slits. Females become sexually mature at about 9 years of age, males only at about 15 years of age. However, sexual practice and experimentation begins much earlier. However, the sexual maturity of cetaceans varies from species to species. Dolphins make love belly to belly.
How do Sperm Whales communicate?
They produce calling sounds and click sound sequences. To the right and left below the blowhole are two paired lips through which air is forced. This is how the clicks or whistling sounds are produced.
Scientists have discovered that not every Sperm Whale clicks in the same way. Depending on where they live, they click differently. That is why researchers have divided them into so-called whale clans. Each clan has its own clicking sounds. Scientists recognise their migration routes and habitat from the sequence of clicks. The clicks are also used for orientation in the sea and for finding food. Their clicks can be heard over long distances. They tell us which clan they come from, what they are doing and experiencing at the moment and also warn of dangers.