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Last week, we very briefly introduced you to ‘Tas’ -one of the newest additions to the third generation of common dolphins in Port Phillip.

Tas is the first known calf of dolphin #41 and the ‘grand-calf’ of V-Nick, one of the original common dolphins who was first sighted in Port Phillip in 2005. But how do we know who Tas’ mum and even grandmother are?

With the right detail, determining cow-calf relationships is fairly straightforward, as adults are often seen with the same young calf over extended periods of time.

However, this was not the case with Tas, requiring our researchers to don their detective hats once again!

Tas was first seen on a vessel survey in March this year when only a few weeks old, determined by its small size and the foetal folds still present on its body. But what we couldn’t figure out was, who was Tas’ mum?

This cheeky calf was seen with both dolphin #41 and dolphin #71 that day, leaving us scratching our heads. Were we seeing double or was something else going on?

Tas with dolphin #41 (March 2023).

Tas with dolphin #71 (March 2023).

It wasn’t until our most recent vessel survey in May when we finally saw Tas again and this time, it was certainly superglued to dolphin #41’s side with dolphin #71 nowhere to be seen. We are now confident that Tas is dolphin #41’s calf, making it a new addition to Gen-3.

Tas with dolphin #41 (May 2023).

So what was going on with Tas and dolphin #71?

We think dolphin #71 was simply ‘babysitting’ Tas, as is often the case in maternal groups. This particular dolphin is also less than four years old, meaning it couldn’t be Tas’ mum, as common dolphins don’t reach sexual maturity until about seven years old.

Confirming Tas as part of the third generation is one aspect of our important work. Carefully monitoring our dolphins and whales enables us to provide environmental managers with accurate and up-to-date information, so that the best decisions can be made for our marine life.

This work simply wouldn’t be possible without our generous supporters. If you would like to help us continue monitoring Tas and its growing family, please donate to our Future Generations Appeal below.

Future Generations Appeal