Why do some animals dump indiscriminately?

Why do some animals poo wherever the fancy takes them, whilst others are more fussy about the locations of their lavatory actions? What triggers pins and needles? How do some fish survive in both fresh and saltwater? And how are new nerve cells born in the adult brain? We burn through your best science questions this week as well as taking a look at Hubble's successor, the James Webb Space Telescope, and hearing how a computer model of a heart can revolutionise cardiac drug design and reviewing the evidence that bacteria were already antibiotic resistant over 30,000 years ago... Like this podcast? Please help us by supporting the Naked Scientists