I think you guys are misunderstanding what Brits mean by that... They value both very little.
I would also answer "Human lives are worth the same as animal lives", simply because Humans are animals.
Never trust the answers to questionnaires with such basic mistakes.
Yeah, I'd like to see the results from the question : I have a gun pointed at your long time childhood friend and one pointed at this cow, now is this cow's life worth the same as your friends life?
What if your childhood friend is the cow and the other entity at gunpoint is an unfamiliar human?
delusion at it's finest, humans are supposedly the smartest beings on this planet and yet this proportion of them are wasting their heads worrying about their former burgers' life, if the animals were meant to be worth as much as us, they would have developed metalworking by now