Читать книгу Springwatch Unsprung: Why Do Robins Have Red Breasts? - Jo Stevens - Страница 24

We noticed one of our smallish koi carp desperately flipping and trying to free itself from what looked like a black ‘growth’ around its head and gills. We netted the fish and discovered a large toad had it tightly in its grasp. My husband forced the toad off the exhausted fish, which has now recovered in a bucket. The toad jumped back into the pond where there are more fish! We’ve never seen this before. Was the toad trying to ‘mate’ with the fish? Jill, Sussex

In essence, yes, the koi carp was on the receiving end of an overexcited toad’s amorous attentions! As soon as night-time temperatures reach 5 degrees Celsius or more, usually in February, adult common toads emerge from hibernation. They have just one thing on their mind: mating. They migrate back to their ancestral pond, often travelling several kilometres and crossing dangerous, busy roads. The males often arrive before the females and will lie in wait, either at the pond itself or nearby, ready to pounce on a potential mate. The smaller male will often piggyback on the larger female as she makes her way to the water.

The male grasps tightly onto the female under the armpits in a special hold called amplexus, Latin for ‘embrace’. During the breeding season the male develops ‘nuptial pads’ on his first three fingers that help him grip onto the female. Males are so intent on breeding that they will often grab toads of the wrong sex or even completely different species like the unfortunate koi carp. Males usually outnumber females at the breeding ponds and competition for mates is high, so it makes sense to grab anything that moves and ask questions later! Actually, males aren’t even that choosy, and have been known to latch on to inanimate objects while in their aroused state.

Male toads will croak their objections loudly if grabbed by mistake, and usually the grabber will let go within a few seconds. Fish can’t be so vocal, though, and there would have been no audible cue to encourage the confused toad to release Jill’s fish. It was lucky that Jill’s husband spotted the embrace when he did, otherwise the koi carp may have endured a long struggle. Male toads are persistent and will often hang on to the female for several days. One female may attract the attentions of several males, resulting in a writhing orgy of warty skin and interlocked limbs – who’d be a female toad?! Eventually the strongest male will be successful and will fertilise the female’s eggs as she lays them, up to 6,000 eggs in long double strings.

One study found that 80 per cent of males returned to the pond where they were spawned, so it’s likely that Jill’s toad was a tadpole in her pond, perhaps before it was stocked with fish. Toads can be long-lived and lucky individuals may reach up to 40 years old, so it might be worth keeping an eye out for this overzealous toad for a few years to come.