6 of the most alarming animal invasions


Some animal invasions occur naturally; in other cases it is all humans’ fault.

Here are six alarming takeovers that could be straight out of the bible, or a horror film.

1. Burmese pythons

Copyright: Everglades NPS

There are fewer animals you’d be less pleased to see invade your area than 12ft constrictor snakes capable of swallowing a deer whole. But that’s what happened in Florida.

The state’s Everglades National Park is now unwilling home to tens of thousands of Burmese pythons. It is thought the problem was started by people who kept them as pets releasing them into the wild.

The snakes have been causing havoc, with severe declines of mammals linked to the slippery customers.

2. Cane toads

Copyright: Liz Poon

Possibly the most famous animal invasion, cane toads were introduced to Australia in the 1930s under a misdirected scheme to control cane beetles.

About 100 of these large, warty specimens were originally released, but numbers have expanded to a whopping 200 million.

3. Rats

Not only is Florida dealing with giant snakes, but huge rats too.

Again, it’s the fault of humans.

It’s thought an exotic pet breeder released a posse of giant Gambian rats into the wild around 20 years ago.

The rodents can grow to about 3ft (0.9m) and weigh up to 9lbs

Elsewhere, rats descended from stowaways on ships have caused havoc on islands with large seabird populations.

The voracious creatures eat eggs, chicks, and even sometimes adult birds, particularly those that nest in burrows or among rocks.

4. Spiders

It sounds like a horror B-movie.

In 2013 the town of Santo Antonio da Platina in Brazil residents looked up to see spiders “raining” down on them.

Although an internet video racked up millions of views, the event wasn’t that unusual. The large, sturdy spider species Parawixia bistriata come out of trees in the evening to build individual webs that connect up into huge structure that can span for 65ft, to catch insects.

It is believed that a gust of wind had caught one of these nets and so to humans below it appeared the skies were filled with spiders.

5. Locusts

Copyright: CSIRO

Locust plagues are a serious problem, and in some countries can be deadly.

The insects have had a devastating effect in many African countries where they have destroyed harvests.

In 1931-1932, known as the year of the locust, plagues of the insect combined with drought and a lack of resources were responsible for the deaths of 100,000 people in the Sahel zone.

6. Jellyfish

Copyright: Emma Birdsey

Since  1996 huge blooms of jellyfish have been appearing along Mediterranean coasts at regular intervals. In 2006, 60 million jellyfish reportedly stung more than 70,000 swimmers along Spain’s coast, forcing some beaches to close.

And large groups of the tentacled marine creatures have wiped out salmon stock around Ireland.

In 2007 a 10-mile-wide bloom of mauve stingers killed some 250,000 salmon in Northern Ireland overnight, and in 2017 invading jellyfish along the west coast of Ireland again wiped out whole stocks of the fish.