Don’t play with your food

During my recent stay on the Morgan in Lanzarote, where I went to do some general maintenance, I was surprised by a visit from the SECAC (see also www.museodecetaceos.org) ladies, a cetacean research organisation and museum, with whom we had often worked. Life on and around the water is always full of surprises, and this time too came as an unexpected surprise.

A False killer whale (Pseudorca crassidens) had stranded on the nearby beach of Papagayo. The whale, one of the smaller species, was still alive when it stranded. The researchers from SECAC were immediately alerted by the local authorities and drove off straightaway. This was an important scientific event for them, and very exciting, because in the nearly 40 years that records of marine mammal strandings have been kept, this was only the third time that a False killer whale had stranded in the Canary Islands.

Dying in their arms

Once there, the young animal died in their arms. Their first impression was that the whale had died of a shark bite, as its back bore the scars of the bite of a large shark. Whenever possible, if a stranded animal dies, it is brought to a location where a necropsy is carried out to determine the cause of death. For this task, the veterinarian and professor, Manuel Arbelo is often called in. We had filmed a necropsy carried out by Manuel and had interviewed him a year ago at the University of Las Palmas.

The False killer whale was brought to SECAC’s osteological research centre. Our friends at SECAC told me what had happened and I made my way there. My first thought when I saw the poor animal was that it had died as a result of eating plastic. We have often seen dolphins and whales playing with large plastic bags. Just like children they do not see the danger and, in the case of cetaceans, there is an extra consideration. Whales and dolphins cannot regurgitate, so if something enters their throats the only thing they can do is swallow – even if it is a poisonous plastic bag. As one of our film themes is plastic in the sea, I grabbed my camera and went to film the necropsy.

Not killed by the shark bites

The first thing the researchers did was measure and visually examine the animal. It was a beautiful creature and not even a year old. Deep black and perfectly streamlined. At first sight the animal looked healthy. The deep shark bites on his back could never have killed him. In general, healthy dolphins and whales are rarely attacked by sharks because they are usually protected by the pod or are simply too fast to be caught. To examine the animal further it was sectioned to allow Manuel to examine the internal organs. Every part of the body was thoroughly examined. Samples were taken of the lungs, liver, heart and other organs, and frozen. They would be examined in the lab later.

Nothing at frst pointed to a sickness or disability which could have been the cause of death, even though the assumption was made that the animal had weakened, become separated from the pod, and was attacked by a shark. My suspicions of plastic grew stronger. One glimpse of the completely transparent intestines showed me that they were empty. The young whale had not eaten in days, maybe weeks. Continuing their examination on the stomach it appeared that the stomach was completely empty too. No plastic and no poisoning.

Now what? Was the young whale simply rejected by the pod, and weakened through loneliness? Or could it have been a virus despite the organs all appearing healthy?

The answer lay in the head

Puzzled, the last step for the team was to examine the head of the whale and this contained the answer. Investigating the head is difficult as the clues are encased in immensely strong bones. The long awaited answer lay in the tip of the tongue. When the large tongue eventually came into view through the underside of the jaw, all became clear. The poor animal’s tongue had been pierced by a large sting from a stingray. The tongue was infected and the sting was so long that it had damaged both the palette and flesh in the lower jaw. The pain must have been enormous and the whale must have endured the pain for weeks. Over time it had weakened and had thus become the prey of the shark.

Apart from the individual tragedy, this was actually good news. The whale had died from natural causes and not from the human hand. For the researchers this was also an important case. While it is documented – from equally tragic deaths – that orcas eat rays it was not known until now that False killer whales also eat rays.

A deadly game

  So you could say that this beautiful animal died from playing with its food. This young whale would still have been feeding from his mother’s milk. But because the sting had pierced its tongue, it became too painful to drink. He became weaker and weaker, and eventually could not remain in the safety of the pod anymore, and became prey.

In the end, it was not plastic that killed this young animal, but playing with his food.

Links:
For general  information about the false killer whale see http://www.cms.int/reports/small_cetaceans/data/P_crassidens/p_crassidens.htm