Author: BBC World Service

Many of us have habits that calm us down in times of stress. Things we find deeply comforting, like sucking our thumb or biting our nails. We might not even be aware we’re doing them, but they play a fundamental role in helping us regulate our emotions.

Our question this week comes from CrowdScience listener and nail-biter, Ash. He wants to know where these habits come from. And since his pet dog is also a nail-biter: do we share these traits with other animals?

Recently, a video of a mouse cleaning up a man’s shed took the internet by storm. Was this a house-proud mouse, or was it the animal's way of making sense of a frenetic environment? An emerging field of scientists focusing on animal behaviour and emotions help us shed some light on such questions.

Along the way we meet a dog training specialist, learn what a sniffari is, go for playtime with a thumb-sucking otter, and visit an OCD clinic. We’ll also be getting tips on how to give your pets the best home environment, and meet an animal enrichment officer in South Africa, who knows how to spot the signs of an unhelpful habit developing.

Contributors: Karolina Westlund, Ethologist, Stockholm University and ILLIS Ben Terry, CBT Therapist, Priory Hospital North London Karin Pienaar, Animal Behaviourist, COAPE International Candice Ward, Animal Behaviourist, Johannesburg Zoo

Jaak Panksepp clip: The science of emotions: Jaak Panksepp at TEDxRainier

Producer: Robbie Wojciechowski Presenter: Alex Lathbridge Editor: Cathy Edwards Production co-ordinator: Connor Morgans Additional recording by Elna Schutz

(Photo: Portrait of border collie puppy biting a curtain. Credit: Rawlstock/Getty Images)

The last great "out of Arica" movement of our ancestors swept out of the northeast of the continent 74,000 years ago. Archaeologist John Kappelman of the University of Texas brings us an update to this complex tale in the form of animal carcasses.

We take a trip to Oxford to meet some of postgraduate researcher Ally Morton-Hayward's archive of preserved brains. Not only is Ally shining a light on these underappreciated brains, she is also using them to unlock a rich treasure-trove of information about our ancestors and how they were preserved.

How do you develop and promote a vaccine against a widespread but neglected parasite? Maria Elena Bottazzi from Baylor College of Medicine is in India promoting their latest development in creating a hookworm vaccine that works against these life-limiting childhood parasites.

And, is the Chandra X-Ray Observatory at risk? In a decision that has shocked astronomers, the functioning telescope is on the chopping block because of NASA budget cuts. We hear from Belinda Wilkes of Bristol University about Chandra’s impressive history and why it should keep going.

Presenter/producer: Roland Pease Researcher: Katie Tomsett Production co-ordinator: Jana Bennett-Holesworth

(Image: Sunset in savannah of Africa. Credit: Anton Petrus via Getty Images)

In a week of headlines about water shortages slowing ships in the Panama Canal and drought in India's Silicon Valley, we look at unexpected ways to manage the world’s water.

Presenter Marnie Chesterton and panellists Chhavi Sachdev in Mumbai, India, and Meral Jamal in Nunavut, Canada, tell stories of innovative ideas being tried in their parts of the world.

Marnie meets water detective Barbara Sherwood Lollar, professor in earth sciences at the University of Toronto, to hear how ancient water can help us plan for the future. Plus, how submersible speakers can help corals, and stories of living underground.

Producer: Dan Welsh with Tom Bonnett, Harrison Lewis, Jack Lee, Katie Tompsett and Emily Preston.