Until I get a proper ref sheet made, here's how I imagine my characters~

Mike
Full name: Michael G██████
Species: Cheetah (Acinonyx jubatus)
Nationality: American
Age: Mid 30's
Height: 5'8 (173cm)
Orientation: Bisexual (preferring men)
Occupation: Youtuber, diving instructor
Diving experience: Certified as a scuba instructor, and an occasional competitive freediver
Static breath hold time: 7:41 - after many years of practice

Nadia
Full name: Nadezhda Lutrova
Species: Eurasian river otter (Lutra lutra)
Nationality: Somewhere in eastern Europe (she won't tell you which country)
Age: Late 20's
Height: 5'3 (160cm)
Orientation: Bisexual
Occupation: Student working on a PhD in mammalian respiratory physiology
Diving experience: Certified in various forms of technical diving
Static breath hold time: 6:05 - without much practice, but naturally talented