Big Week At The Zoo (C5, 8pm)

NEW series. Helen Skelton and Nick Baker return to Yorkshire Wildlife Park to celebrate the work of British zoos. In the first edition, they drop in on three one-month-old endangered tiger cubs, Yorkshire Vet star Peter Wright befriends a tame tapir. JB Gill assists as a pygmy hippo is given a dental procedure and helps determine the sex of a baby sloth, while attempts are made to encourage two rare Chinese alligators to breed.

Who Do You Think You Are? (BBC1, 9pm)

CANADIAN comedian Katherine Ryan has become one of the most ubiquitous faces on UK TV in recent years. She has appeared in shows such as QI, Have I Got News For You, Mock the Week and 8 Out of 10 Cats Does Countdown on many occasions. She’s the latest celebrity to take part in the genial genealogy show, and an investigation of her family history leads her to a Methodist minister and his family in colonial Nova Scotia, cod traders in Newfoundland, and eventually to her English roots in Dorset.

Rams: Principles Of Good Design (BBC4, 9pm)

DIETER Rams has left an indelible mark on the field of product design. His work at Braun, Vitsoe and his influence on Apple has been considerable. He has a list of principles for designs, they must be innovative, useful and aesthetic. So why, at 87, does he now regret being a designer? Find out in a documentary that offers views on consumerism, sustainability, and the future of design. Brian Eno provides the score.

Call The Cops (C4, 9pm)

DOCUMENTARY going behind the scenes with the Devon and Cornwall police force, showing the critical decisions that the communications and control centre team makes each day. The first edition covers the Easter bank holidays, and incident manager Adele must decide which jobs to prioritise, with only limited resources. The weekend begins with a violent arrest, which uses up all of the unit’s available response officers, while the only dedicated traffic officer is called to an accident.