OTWO Magazine September 2019 | Page 68

The bay is considered a breeding and feeding ground for a significant population of short-beaked common dolphins. Also found in the area are bott- lenose and striped dolphins but are seen less fre- quently. Striped dolphins occasionally mix with com- mon dolphins, but bottlenose and common dolphins do not usually interact and tend to avoid each other. Even so, the story of this unique bottlenose and common dolphin hybrid began with a lone female bottlenose dolphin commonly known as Billie. Billie was well known amongst local marine bio- logists, having been observed for over 10 years in- teracting with groups of common dolphins. Before 2016, she was also spotted assisting common dol- phin births and leading newborns to the surface on three occasions. On the 11 August 2016, Billie was seen raising and pushing a newborn calf to the surface. No other dolphins were present at the time, and after compa- ring previous photographs taken of Billie, they con- cluded that the calf belonged to her and that it was possibly a hybrid. After this unique find, Rocio began collecting standardised data such as the date, time and loca- tion of each sighting. This data was collected over 10 months, with the pair seen almost daily. Out of 355 sightings, they were observed 104 times within nursery groups of common dolphins. They examined the young dolphins’ features and found that its length and robust body showed si- milarities to that of a bottlenose, while its lateral striping, colouration and criss-cross patterns were characteristics of common dolphins. They also studied the pair to determine more about their relationship by monitoring their inte- ractions. They observed Billie exhibiting continuous parental and nurturing behaviours and nearly always having near-body contact with the calf. They also ob- served the pair rubbing against each other and cha- sing each other, which are typical signs of mother and calf behaviour. Collecting DNA samples from the calf was also considered but were not taken as the process was deemed too risky with a possibility of endangering the calf’s health. After compiling all of their findings, they conclu- 66 OTWO 02 / SEPTEMBER 2019 OTWO 02 / SEPTEMBER 2019 ded that this had to be a one of a kind bottlenose/ short-beaked common dolphin hybrid, never before seen in the wild. Sadly, the hybrid has not been seen since June 2017, leading the team to believe that it may no lon- ger be alive. But considering how rare marine mammal hybrids are in the wild, there have been a few other disco- veries over the last couple of years in other parts of the world. In 2017, just off the coast of the island of Kauai, another unique hybrid was spotted: a cross between a melon-headed whale and a rough-toothed dolphin. This male hybrid had a dorsal cape matching that of the melon-headed whale and the blotchy colour pattern of a rough-toothed dolphin. DNA samples confirmed that his mother was a melon-headed whale meaning the hybrids father was a rough-too- thed dolphin. It was amusingly, but mistakenly, given the moni- ker of ‘Wholphin’. However, as melon-headed wha- les are in-fact a member of the dolphin family, this fun name is unfortunately quite misleading. Last year, scientists also discovered that a unique hybridisation between a narwhal and a beluga took place over 30 years ago. In the late 80s, an Inuit subsistence hunter killed three of these possible hybrids but had no idea what they were. They had flippers that were similar to a beluga, but the tails were like that of a narwhal. They were neither white nor mottled but completely grey. He kept one skull which was later examined by a scientist in Copenhagen in 1990 who hypothesised that this was a narwal/beluga hybrid. But thanks to DNA analysis performed by the University of Den- mark, it was confirmed to be true just last year and has been nicknamed a Narluga! With this wonderfully unique find of a dolphin hybrid right here in the bay, it further highlights the magnificent ecological diversity that the Straits have to offer. Due to how busy the Straits are, shipping and fishing pose the greatest threats to dolphins and other marine mammals in the area. Researchers and conservationists have called for better environ- mental education and further protection for marine mammals residing in its waters. 67