Natural World's 'Two Tonne Tusker' is airing in the UK on Friday 18th October at 9pm on BBC2.
"Sivuqaq is an 18 year old, larger than life captive Pacific walrus. By now he should be a dad but things have not worked out. This is where reproduction scientist Holley Muraco comes in.
Holley is taking on the biggest challenge of her career - trying to help Sivuqaq become a parent. Yet walrus love is a mystery - even pandas have been bred more successfully than walruses. Holley hopes that by visiting Sivuqaq's wild cousins in Northern Alaska she'll find out more about the intricacies of walrus breeding."