Tag Archives: Invasive Species

Galapagos Giant Tortoise

Galapagos Islands Tourists

Tourists at a Tortoise Sanctuary in the Galapagos Islands.

A Galapagos Giant Tortoise retreats into his shell as tourists in another group gather in the highlands of Santa Cruz Island in the Galapagos Islands to learn more about this magnificent creature.

I visited the islands with my family in April 2015, and we toured the highlands was our first day.  It was truly thrilling to see these giant tortoises in their natural environment. I remember seeing one in a zoo when I was a child. Children even rode them (I think I even did), which is a bad idea, and of course no longer allowed. They aren’t afraid of humans, but do make a chuffing noise if you startle them.

The nasty little fire ant has invaded the Galapagos Islands.  Here's a fire ant hill in the highlands of Santa Cruz Island of the Galapagos.   The ants found me before I found them, unfortunately.  There are efforts in the Galapagos to rid the islands of invasive species, which have caused great damage to the native animals and plants.

The nasty little fire ant has invaded the Galapagos Islands. Here’s a fire ant hill in the highlands of Santa Cruz Island of the Galapagos. The ants found me before I found them, unfortunately. There are efforts in the Galapagos to rid the islands of invasive species, which have caused great damage to the native animals and plants.

The tourists in the pictured group are wisely wearing rubber boots. Our guide offered us boots, too, but I was happy wearing my comfortable “sporty” flip flops, relieved to let my feet breathe after a long trip.  Bad idea.  I successfully evaded puddles and tortoise poop, but I stepped right onto an ant hill teeming with fire ants, an invasive species in the Galapagos. This was within two hours of my arrival on the island of Santa Cruz. I got about six painful, itchy stings on my toes. I’m no stranger to fire ants, so I know enough to wear closed shoes in grassy areas in Texas, but I wasn’t prepared for the little devils in the Galapagos.

Galapagos is an old Spanish word for tortoise. The signs at this ranch warn visitors not to feed or touch the “galapagos.” The tortoises are now more commonly known as “tortuga” in Spanish. (At the bottom of this post is a link explaining how the islands were named.)  The Galapagos Island archipelago has been described as one of most scientifically important and biologically outstanding areas on earth, according to UNESCO in 2001.  My week there was amazing, wonderful and incredible, despite fire ants (and various other mishaps.)

Galapagos Giant Tortoise Poster

This Giant Galapagos Tortoise paused to give us a questioning look as he crossed the road in front of our car in the highlands of Santa Cruz Island in the Galapagos Islands. He is king in this place! (Or perhaps she is queen!)

Baby Galapagos Giant Tortoise Postcard

A yearling baby Galapagos Giant Tortoise, being raised at the Charles Darwin Research Station on Santa Cruz Island in the Galapagos Islands. Introduced predators threaten the eggs and young of the Giant Tortoise, so tortoise eggs are gathered, hatched and reared at the station.

Galapagos Giant Tortoise

Wise old Galapagos Giant Tortoise.

About the Galapagos Islands.

How the Galapagos Islands Were Named.

The Difference Between Turtles, Tortoises and Terrapins.

About Lonesome George.

GIANT TORTOISE FACTS: The Galapagos tortoise or Galapagos giant tortoise (Chelonoidis nigra) is the largest living species of tortoise and the 14th-heaviest living reptile. Modern giant tortoises can weigh up to 5oo pounds (250 kg); even larger versions, now extinct, roamed every continent except Antarctica and Australia. Today, they exist only the Galapagos Islands, and Aldabra in the Indian Ocean. The tortoise is native to seven of the Galapagos Islands, a volcanic archipelago about 620 miles (more than 1,000 kilometers) west of the Ecuadorian mainland. With life spans in the wild of over 100 years, it is one of the longest-lived vertebrates. One of the most famous was “Lonesome George,” who died in 2012, the last Pinta Island Tortoise.

Shell size and shape vary between populations. On islands with humid highlands, the tortoises are larger, with domed shells and short necks – on islands with dry lowlands, the tortoises are smaller, with “saddleback” shells and long necks. Charles Darwin’s observations of these differences on the second voyage of the Beagle in 1835, contributed to the development of his theory of evolution. Tortoise numbers declined from over 250,000 in the 16th century to a low of around 3,000 in the 1970s. This decline was caused by exploitation of the species for meat and oil, habitat clearance for agriculture, and introduction of non-native animals to the islands, such as rats, goats, and pigs. Conservation efforts, beginning in the 20th century, have resulted in thousands of captive-bred juveniles being released onto their ancestral home islands, and it is estimated that the total number of the species exceeded 19,000 at the start of the 21st century. Despite this rebound, the species as a whole is classified as “vulnerable” by the International Union for Conservation of Nature (IUCN).

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Why Did The Mongoose Cross The Road?

When it stands, this mongoose looks like its relative the Meerkat.

Years ago in a biology class, I learned about the Indian Mongoose’s introduction to Hawaii (in 1883) as a predator to kill the rats that were thriving in sugar cane fields.  Well, like so many ideas like this, it was a disaster (rabbits to Australia, for example…) The mongooses ate the native birds and their eggs instead.

I’d forgotten about the mongoose  until I recently saw one dashing across the road on the Big Island of Hawaii, where they are pests. As it dashed, it looked like a small ferret.  Every so often, my husband and I would see another one running like mad across the road.  I was never fast enough with my camera.  Finally, I did get a few blurry photographs of a mongoose that seemed to live in the bushes of someone’s yard outside of a botanical garden.  When it stands, it looks like a meerkat, which is one of its relatives.

Standing here, he looks like his relative the Meerkat. He may have a burrow in the yard of this house.

From wikipedia: The 1800s were a huge century for sugar cane, and plantations shot up on many tropical islands including Hawai’i and Jamaica. With sugar cane came rats, attracted to the sweet plant, which ended up causing crop destruction and loss. Attempts were made to introduce the species in Trinidad in 1870 but this failed. A subsequent trial with four males and five females from Calcutta however established in Jamaica in 1872. A paper published by W. B. Espeut that praised the results intrigued Hawaiian plantation owners who, in 1883, brought 72 mongooses from Jamaica to the Hamakua Coast on the Big Island. These were raised and their offspring were shipped to plantations on other islands. Populations that have been introduced to these islands show larger sizes than in their native ranges. They also show genetic diversification due to drift and population isolation.

Only the islands of Lana’i and Kaua’i are (thought to be) free of mongooses. There are two conflicting stories of why Kaua’i was spared. The first is that the residents of Kaua’i were opposed to having the animals on the island and when the ship carrying the offspring reached Kaua’i, the animals were thrown overboard and drowned. A second story tells that on arriving on Kaua’i one of the mongooses bit a dockworker who, in a fit of anger, threw the caged animals into the harbor to drown.

The mongoose introduction did not have the desired effect of rat control. The mongoose hunted birds and bird eggs, threatening many local island species. The mongooses bred prolifically with males becoming sexually mature at 4 months and females producing litters of 2-5 pups a year.

If that isn’t bad enough, Mongooses can carry the infectious bacterial disease Leptospirosis.

About the mongoose.

More about the mongoose.

News report about trapping Mongooses.

 

This mongoose ran back and forth on this road on the Big Island of Hawaii near Hilo several times. He kept checking to see whether I'd left.

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