Herts Hogline founder Lynne Garner picked up Derek when he was just a few weeks old. He'd been rescued by a local vet and was in bad shape.
"He [weighed] less than 100 grams, and they [hedgehogs] have to be 600 grams to survive the winter," Garner told The Dodo. Derek also had a large, infected wound - possibly from a bird attack - which Garner cleaned and treated carefully over the next few weeks.
The wound made Derek very anxious - so anxious, in fact, that he now suffers from stress-induced alopecia, or spine loss. The condition has caused him to lose nearly all of his spines - a phenomenon Garner said she hadn't seen at Herts Hogline in 25 years.