Rats!

Over the last few weeks I’ve been noticing extensive damage to shrubs and small trees. The bark has been removed over long sections of living and (now) dead plants. I wondered what could be doing this.

I had a few ideas. The first possible culprit was pigs. I’ve been seeing a lot of pig sign out in the woods, and marshes. And, I finally glimpsed a few live ones along the road near Treasure Key. Anyways, I figured it could be pigs chewing bark off trees. This suspicion was short lived. The next likely critter was a Hairy woodpecker. These medium-sized, black and white birds will peck at narrow branches in their search for wood-boring insects. This seemed a reasonable hypothesis, but I was fairly hesitant to believe that the degree of damage I was seeing was caused by these little birds – at least I’d never seen them do anything like that before.

Yesterday, I think I figured it out. The answer is RATS! I was noticing more of the chewed up bushes around Hill’s Creek when I almost stepped on a dead rat! I think the rats I’ve been seeing in the bush, and pictured above, are black rats (Rattus rattus). Of course it was rats chewing the bark. They must be starving out there if they’re resorting to bark. On this tiny island I was working on, sea grape was the target of the rats (see photos above). However, in other areas I’ve noticed a variety of shrubs and small trees chewed.

Typically, introduced rats are a serious ecological problem worldwide, especially on islands like New Zealand. They destroy seedlings and consume small animals threatening the integrity of many ecosystems and the survival of species. They are firmly established on Abaco, and I’ve seen many over the last month. But for various reasons I found this interaction between trees and rats interesting. Most interesting, is the fact that most areas in The Bahamas have very few vertebrate herbivores. Fossil records point to Hutia, iguanas, and tortoises as the primary herbivores before the arrival of humans 1000 years ago. These large herbivores are now extinct or extirpated from most of their former range, leaving the island vegetation largely free from browsing or grazing pressures. Could rats be filling that ecological void?  Or, are chewed shrubs evidence of an ecological harm due to an invasive species? I don’t know. Does anyone know if Hutia chew bark like this?

Anyways, I think the mystery of the chewed sea grape is over. Now, I’ll keep an eye out for more rat herbivory!

By | 2017-12-01T14:01:57+00:00 January 28th, 2016|Categories: Featured, Invasive Species|Tags: , , , , , |2 Comments

About the Author:

Sean Giery
I am an evolutionary ecologist in the Department of Ecology and Evolutionary Biology at the University of Connecticut. My research investigates how basic ecological interactions control fundamental biological processes such as sexual selection, communication, and predation.

2 Comments

  1. Sean Giery
    Sean Giery January 28, 2016 at 10:36 pm

    A reader looked up some information on the wild Cuban Hutia and sent along some information on their diet. I’ve decided to add that information here.

    As per wikipedia, “They are omnivorous but eat mostly bark, leaves and fruit. Occasionally they will take small vertebrates such as lizards.”. Also, BNT says this about the Bahama hutia, “Hutias are herbivores (plant eaters), feeding on the leaves and twigs of a variety of succulent shrubs. Some of their food sources are bay cedar (Suriana maritma), buttonwood (Conocarpus erectus) leaves and twigs, and swamp bush (Forestiera segregate).”

    So, it appears that twig chewing is a pressure that woody species have experienced for millennia. In this case, perhaps the rat is actually restoring some formerly lost ecological interaction. I sure don’t know. But maybe it’s worth a bit of thought.

    Thanks for the info!

  2. lisa February 8, 2017 at 2:17 am

    rats are the biggest problem not only in bahamas but also in every part of world

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