The evolution of animal species depends on the environmental conditions of Earth. When we look at the history of our planet, we can see that some animal species managed to thrive in different geological periods, developing millions of years ago. Here is a list of the top 10 oldest animal species on Earth.
10Martialis Huereka-120 million years old
Martialis is the oldest ant species ever discovered in the Amazon rainforest. Its name, which means ‘ants from Mars’, was because of this species’ unique behavior compared to other known ant species on Earth. Several studies estimate this species evolved on Earth about 120 million years ago. The collected ant specimens prove they prefer low-light environments like leaf litter or rotting wood.
This species is pale in color, 3 millimeters long, and has no eyes. They used to live in the soil, and the huge, long front legs may have helped them to capture prey. Their legs are relatively thin and lack the characteristic for digging activities. The discovery of Martialis Huereka is a significant advancement, as it helps biologists conduct in-depth studies of other ant species.
9Frilled Shark – 150 million years old
The Frilled shark is a prehistoric species that lived deep below the sea surface in dark waters. First discovered in Tokyo, Japan, in 2007, this species is regarded as a “living fossil” as it appeared on Earth 150 million years ago. With its 300 trident-shaped teeth arranged in 25 rows, this 5-foot-long shark has a strange-looking mouth that seems much larger than other shark species.
It thrives in the ocean’s depths due to its hydrocarbon-rich liver and oily body. Furthermore, frilled sharks are very rare worldwide due to over-pollution and changes in ocean temperature. Additionally, frilled sharks have a sudden attacking power over their prey.
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8Horseshoe Shrimp – 200 million years old
Horseshoe shrimps first appeared on Earth around 200 million years ago, at the same time as dinosaurs. These tiny creatures thrive in shallow waters and can change colors to blend in with their surroundings. As keystone species, they play a crucial role in many marine food webs by serving as a primary food source for various predators.
Despite being only 2 to 4 millimeters long, horseshoe shrimps can survive in any weather conditions and geological variations. When pools of horseshoe shrimps dry up, their eggs can remain dormant for many years, ensuring their species’ survival. Scientists discovered this extraordinary marine species in 1955 and observed the growth of horseshoe shrimps by re-wetting several years-old eggs.
7Sturgeon – 200 million years old
Sturgeons are the oldest of the bony fish family, having evolved 200 million years ago. They live in Eurasia and North America and are the largest freshwater fish in North America. During the winter, they migrate to distant places such as rivers or the shores of freshwater lakes to breed. Their eggs are small, sticky, and numerous.
Young Sturgeons rapidly grow until they attain maturity, after which their growth continues slowly for several years. Sturgeons can grow up to 5.5 feet long and weigh between 200 kg and 600 kg. Unfortunately, sturgeons are now on the critically endangered species list due to overfishing. Sturgeons lay many eggs at a time, but humans harvest them at a high rate, which poses a significant threat to these deep-sea creatures.
6Coelacanath – 360 million years old
Coelacanths are a critically endangered species of fish that first evolved around 360 million years ago. There are two types of coelacanths in the world, and they primarily live in the coastal regions of Africa and Indonesia. These unique fishes are 6.5 feet long and weigh as much as 90 kg. They are the only living animals with a fully functional division separating the ear and brain from the nasal organs and eyes.
Coelacanths can be found at depths of up to 2300 feet below the ocean’s surface and can live up to 60 years. Coelacanths move uniquely, like a trotting horse, using their legs to help them navigate. Their electro-sensory organ is highly developed, allowing them to detect prey in the ocean easily. Additionally, coelacanths can widen their mouths to catch larger prey.
5Horseshoe Crab – 445 million years old
Horseshoe crabs are one of the oldest living creatures on Earth, having originated 445 million years ago. They usually live in shallow ocean waters across the globe. These prehistoric creatures have a hard exoskeleton, long tails, and spines and are more closely related to scorpions and spiders than crabs. The name ‘horseshoe crabs’ is because their rounded head resembles a horse’s shoe.
The head is the largest body part and contains most of its nervous and biological organs, including the brain, heart, mouth, nervous system, and glands, all protected by a large plate. Their head also houses their largest set of eyes, with nine eyes found throughout the body. While horseshoe crabs mainly use two large eyes, others control their movements, and the light receptors help sense ultraviolet rays.
4Nautilus – 500 million years old
Nautilus is a marine mollusk that evolved 500 million years ago, even before the era of Dinosaurs on Earth. It is the only surviving member of its vast shellfish group. Nautilus typically inhabits tropical waters and can be found in regions such as Andaman, Fiji, and the Great Barrier Reef, at depths of up to 2200 feet. Nautilus is a living fossil characterized by numerous chambered shells covering its body, making it appear like an octopus.
While the animal occupies the largest chamber of the shell, the other chambers function as ballast tanks, which aid the Nautilus in swimming. The Nautilus uses its siphuncle to regulate buoyancy as it travels through the water column. The creature’s mouth has 100 tentacles and a muscular hood on its shell, which protects it from predators.
3Jelly Fish – 550 Million years old
The umbrella-headed Jellyfish live in cold, warm, deep ocean water and along coastlines. They are the oldest multi-organ animals, having evolved in the world’s oceans 550 million years ago. Despite having no brain or nervous system, they can eat and discard waste through an opening inside their bell-shaped body.
Jellyfish come in various shapes and colors, and around 90 percent of their body is water. They can also eat other Jellyfish. The box jellyfish is considered the most venomous species on Earth, with its tentacles containing over 5,000 stinging cells. These tiny cells can stun or paralyze their prey before the Jellyfish consumes them. Although Jellyfish do not usually attack humans, accidentally touching one can be deadly.
2Sponge – 580 million years old
Sponges are a type of marine animal that resembles a plant. They have appeared in the world’s oceans before 580 million years. Most of the 5,000 different sponge species reside in colonies at varying depths within the ocean. Sponges don’t possess any internal organs, arms, or heads. However, they can regenerate lost body parts uniquely, and a new sponge will grow from the old one.
The body of sponges houses many canals and serves as a habitat for numerous small aquatic animal species. These animals play a critical role in coral reef ecosystems as a diverse sponge population helps maintain water quality by filtering water, collecting bacteria, and processing carbon, phosphorus, and nitrogen. Even in nutrient-deficient coral reefs, some sponge species can make carbon biologically available, thus fueling productivity throughout the ecosystem.
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1Cyanobacteria – 2.8 billion years old
Cyanobacteria are the oldest living organisms, originating 2.8 billion years ago. They were the first microbes to produce oxygen through photosynthesis, which helped convert Earth’s atmosphere into an oxidizing one. Often called green-clue bacteria, cyanobacteria are photosynthetic, containing chlorophyll pigments like green plants.
In addition, they have various yellowish-blue carotenoid pigments called ‘phycobilin,’ which give them their iconic blue-green color. They can also fix atmospheric nitrogen, transforming it into compounds for use by living cells. Cyanobacteria can serve as food for fish and contribute a significant amount of oxygen to the atmosphere. They can spread widely in aquatic and terrestrial settings, alone or in colonies, and reproduce through microfission.
