What makes dolphins beach themselves

When it comes to Australian humpback dolphins—a dolphin species that was only scientifically described for the first time in —the behavior is only consistently seen in one location. The most famous being in Charleston, South Carolina, around which a dolphin-watching industry developed.

I have observed this behaviour multiple times since , once I understood the conditions needed by dolphins to strand feed. However, the first video of partial strand feeding was captured only in Last year for the first time we have been able to document extensively this behaviour from the air using drones," he said.

For his recent observations, using drones Cagnazzi filmed a pod of dolphins living in the Fitzroy River in the eastern Australian state of Queensland.

The Australian humpback dolphins in this river are the only members of their species in the country that are known to reliably engage in this behavior. The dolphins have a rivalry, though. Gulls and herons have learned to follow the hunt and hop in to catch their own food.

In competition with the birds, the dolphins will propel themselves further up the bank to catch more prey. This presents a big risk of stranding themselves on the shallow mudbanks.

It is well known that mankind can have averse effects on the natural world. Dolphins can become caught up in fishing nets as bycatch: unintentional prey of fisherman angling for others. Some stranded dolphins even bear marks of the nets that cut into their skin.

In some cases, strands of rope get wrapped around them or caught on their fins. In dire cases, they can lead to stranding. Notoriously bad for the environment, oil spills will tragically redirect dolphins to the only clean space left: the shoreline.

There are many organizations, societies, and non-profits that work to protect marine mammals. A quick Google search will bring up any conservation efforts in your area, along with hotlines to call. Sometimes, smaller dolphins become beached because they have taken refuge from orcas and other predators in shallower waters or because they have ventured too far into shallow areas when hunting shoals of fish. Occasionally, individual animals are also washed ashore dead after being previously injured by collisions with ships, fishing nets or shark attacks or becoming ill from infections or parasite infestation.

High-performance military sonar devices in particular massively impair the orientation of marine mammals. In addition to natural factors, man-made underwater noise from ships, icebreakers, drilling platforms or military sonar equipment can also massively impair the orientation and communication of marine mammals.

They flee the strong sound waves in a state of confusion. And since the density of water is much higher than that of air, sound propagates underwater about five times faster than in the air.

Military sonar operations employing very loud sounds have particularly drastic effects. The sonars, which are louder than decibels, triggered the formation of gas bubbles in the blood vessels and organs of marine mammals as happens with diving sickness , obstructing the blood supply and leading to their death.

When a whale stranding is discovered, there is usually not much time left. Teams of helpers can do little more than try to cool the stranded animals, keep them moist and combine forces to get the heavy animals back into the sea as quickly and gently as possible.

In some countries, hotlines have been set up so that as many helpers as possible can be mobilized quickly. For many exhausted animals, however, even these immediate measures often come too late. The high-tech devices offer a new insight into the animals' hunting techniques and social behavior. This picture shows a family of orcas off the Canadian coast. Six rotors and a high-resolution camera: The drone hovers 40 meters feet above the water to get the best pictures, without disturbing the animals.

Sometimes, the drone manages to capture intimate moments - such as these two killer whales nuzzling each other. Surveying a population size becomes much easier with the help of the drones. Researchers are better able to monitor the number of animals and their physical condition over a longer period of time, and compare it with data from other whale pods.

Whales don't eat during their long travels into the Arctic, so it's crucial for them to have a stock of blubber - a special type of body fat - when they start their journey. This is especially important for lactating females. Despite weighing several tons, the female gray whale on the left may even be a bit underweight. The NOAA scientists have a special permit in order to get that close to the orcas and gray whales. To protect the animals, whale watchers must typically keep a distance of meters - which means that pictures like these will remain a special treat.

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