We visited both the otters and butterflies a few summers ago (pre children) and really enjoyed it, so were keen to take our children (age 4-5) there this winter. In winter the butterflies are sleeping so that part is closed, but we were delighted to have the otters almost to ourselves and a near-private tour from the keeper at feeding time with lots of fascinating information about otters, the sanctuary and the individual otters there. Although it's small, outdoors and can be muddy, it's brilliant to see and hear the otters and the children's faces lit up. Usually the steam trains next door would be a great follow-up activity to get lunch in Totnes, but they were unfortunately closed due to a landslip. Lunch at the House of Marbles not far away worked great instead.