There are several factors that affect animal lifespan, such as metabolism, age of sexual maturity and whether the animal is predator or prey. Size is also a factor. Smaller animals tend to have a shorter lifespan than larger animals, mainly because most small animals also have a fast metabolic rate and are prey animals for larger predators. This, however, is evened out when it comes to reproductive rate, with smaller animals generally able to produce more young than larger animals.
In dogs, however, smaller breeds like the Chihuahua, Pomeranian and terrier breeds tend to be the longer-lived dog breeds. According to recent research by a university in Germany, this is because large dogs tend to age faster, and so develop more age-related illnesses and disorders, such as bone disorders, heart conditions and hormonal dysfunctions.
Just take a look at this list of longest living animals below and you’ll notice that most of them are huge. Before we tackle them, though, let’s take a look at one species of jellyfish that is too good for the list —the Turritopsis dohrnii.
The Turritopsis dohrnii is known as the “immortal” jellyfish. This is because when it is starved, hurt, threatened or stressed in any way, it ages in reverse. That’s right. It gets younger. You see, jellyfish usually undergo four stages — planula (which is the larval stage), polyp, ephyra and medusa. When threatened, the Turritopsis dohrnii goes from medusa to polyp, and not just one polyp, but possibly a colony of polyps that can all develop into adults. As if that’s not amazing enough, this jellyfish can do this over and over again — endlessly, which means it can live forever unless it is eaten or succumbs to disease.
Now, on to the animals that have long lifespans:
1. Turtles (80 to 250 years)
Turtles and tortoises are some of the longest living animals. Because sea turtles spend most of their lives in the water, it is hard to estimate exactly how long they live, though scientists peg their lifespan at around 80 years.
Tortoises live longer. In fact, the oldest tortoise to ever live was 188 years old. Another tortoise, named Harriet and brought to England by Charles Darwin himself, was believed to have reached 175 years old. Currently, the oldest living tortoise is a Seychelles giant tortoise named Jonathan, who may be as old as 182 years.
On average, tortoises live for 120 to 250 years. The giant tortoises such as the Aldapra giant tortoise and the Galapagos tortoise, which can weigh up to 550 pounds (250 kilograms), are particularly long-lived, having lifespans of over 150 years.
Turtles in general have a slow metabolic rate, which contributes to their long lifespan. A slow metabolic rate, however, can have a downside — it means that symptoms of an illness do not manifest until it is too late, so turtles in captivity need regular trips to the vet.
2. Whales (30 to possibly 200 years)
Most whales have a lifespan of between 30 to 90 years. The bowhead whale, however, is believed to have a lifespan of over 100 years, possibly up to 200 years. This belief came at the heels of the discovery of a bowhead whale found with the head of a harpoon embedded in its neck, the harpoon being one of the weapons used in the 1890 whale hunts, as well as other scientific research.
Next to the bowhead whale, the fin whale, blue whale and are the longest-lived, with records of lifespans over 100 years. All these whales are baleen whales, predatory whales that feed mostly on tons of krill.
Though technically not a whale but a dolphin, the killer whale is also long-lived. Its average lifespan is 60 to 100 years, longer for females. The oldest living killer whale on record, though, is 103 years old.
Killer whales live long because they are the ocean’s top predators, even feeding on young blue whales, and because they live in groups and look out for each other.