We’re up to rat kill number 5 in our Ōtepoti urban trap. The last few rats have been partially eaten in the trap, I am expecting by another rat.
We’re using a Victor from Predator Free Dunedin, baited with a cheese, peanut butter and jam combo on advice of one of our kids.
I’ve just read Tips for Catching Norway Rats which has some good pointers on rats eating rats. So this I guess is normal.
I’m wondering if we have one big rat (who we’re now fattening up?!) or if this is just telling us there’s more rats to catch. How could we tell? Are there tells from the state of the remains?
(I’ve added photos to the kills if that’s useful.)
These rat carcasses were each partially or fully eviscerated by something small enough to get into the City Sanctuary trap box. I had omitted that detail above
Looked like it was dining on some preferred internal organs and having cheese pb+j for dessert.
Today it seems our strategy of “keep baiting, even if it fattens the big one” has paid off; there was a much larger rat, and nobody came along and gnawed at it or finished off the bait.
Today’s kill is darker, larger and has a tail about the length of the Victor trap, which is apparently 7". Previous kills had brown/grey fur and a tail about 4".
Many decades ago we lived in a bush hut - but before we could move in we set rat traps.
We caught many rats and most were consumed by other rats - until the number of eaten and caught rats decreased - I.E as teh number sof rats decreased so did the consumption rate eventually both stopped altogether…so I would say that’s totally normal .
Initially I agreed with the post that said it’s possibly due to a cat, until you mentioned they were in a trap box. So having seen rats eaten in traps I would suggest it’s another rat, but haven’t seen one eaten as severely as the one pic you posted there where it’s carcass is almost completely nailed. Looks like brown rats you have caught, shorter tail and smaller ears. I caught a brown rat which was half eaten, caught a bigger brown rat the next day, after that nothing. Have caught dozens of ship rats, sometimes 3 or 4 in a row on consecutive nights, but never seen them eaten. Maybe brown rats are the more vicious and predatory species…even amongst themselves. Certainly harder to catch.
For Differentiating between species, see page 14 of this PF2050 document which references details I had no idea about before, like colour of upper side of hind foot
Ship rat - Uniform colouring over whole foot, usually dark.
Norway rat - Always completely pale.
Kiore - Outer edge dark near ankle, rest of foot and toes pale.
It seems from here that unless caught on Stewart Island or remote parts of fiordland NZ Rat catches are unlikely to be Kiore.
