I'm a recently graduated marine biology MRes student from the University of Plymouth. I'm currently looking for jobs in the marine biology field, with a particular interest in behavioral research, and marine mammal and sea turtle ecology. This is a blog about things that I find interesting including conservation, marine biology, evolution, and other sciencey things!
So recently I made a blog about tool usage in non-human animals to show the wide range of intelligence in different species. However, there is one species, or more accurately group of species, that I didn't mention in that post which cannot be overlooked when discussing the most intelligent animals on the planet.
Left-Right: Giant Pacific Octopus, Enteroctopus dofleini; Flamboyant Cuttlefish, Metasepia pfefferi; and the Hawaiian Bobtail Squid, Euprymna scolopes.
The octopus, squid, and cuttlefish pictured above are all Cephalopods, and are in fact grouped together in the subclass Coleoidea. Cephalopods are considered the most intelligent invertebrate group for several reasons. Firstly the brain-body mass ratio, a common rough estimate of intelligence in species, is higher among octopuses and cuttlefish than any other invertebrate. Bigger brains relative to body size is considered a good estimate of animal intelligence, although the estimation is imprecise and not fool-proof. Another example of Cephalopod intelligence is their tool use, which I touched on in other species previously. The veined octopus, Amphioctopus marginatus, has been observed collecting discarded coconut shells on the sea floor, cleaning them out, and then carrying them awkwardly away.
Veined octopus, Amphioctopus marginatus, carrying coconut shells to use as shelter.
This behaviour might seem odd at first, but all becomes clear when the octopus settles down and constructs a "tent" out of the shells for protection. This collection and preparation of objects, as well as the continued and clearly conscious use of them for a specific purpose fulfills all the requirements of tool usage which, as discussed in previous posts, is a major indicator of intelligence. While some of you may be surprised at the intellect of these humble molluscs, their dexterity, and curiosity have been documented several times before. Octopuses held in captivity have been known to break bits of their tanks causing aquariums to flood, spray feeders with water, juggle tank mates, and smash aquarium tanks with rocks. There are also multiple stories (and you've probably all heard one of these) about octopuses escaping their tanks at night and visiting some of their fellow aquarium species. Specifically stories mention a nearby lobster tank which is invaded by the eight-legged adventurer who then proceeds to kidnap several lobsters. Aquarium staff are reported to return the next day and find they are missing lobsters. The stories go on to describe investigations into lobster thieves, added security measures, and the eventual discovery of the culprit in the act. Following examinations of the octopus's tank the remains of discarded lobsters are found secreted away beneath rocks.
Octopus displaying its dexterity, strength, and ingenuity by opening a jar while inside it.
Cuttlefish and other Cephalopods are renowned for their amazing, near instantaneous, color changing capabilities. While this ability is certainly beneficial for camouflage, it has also been adapted in some species of Cephalopod for use in communication. Species such as the Caribbean reef squid, Sepioteuthis sepioidea, which utilizes chromatophores, pigment rich cells, to flash color signals to other squid, usually as part of a courtship ritual. The squid can even send different signals to fellow squid on opposite sides simultaneously!
Sir David Attenborough discussing various amazing abilities of Cephalopods.
While these creatures are unquestionably intelligent scientists are just beginning to discover how smart they really are. Research has shown that octopuses have on average around 130 million neurons in their brain which doesn't seem like a lot when compared with the 100 billion in the human brain. However, two-thirds of the neurons in an octopus's body are spread throughout it's arms rather than concentrated in the cerebral cortex like vertebrates. In terms of total number octopuses actually have more neurons than several species of rats and mice. The location of the neurons in their arms is theorized to grant them the ability to operate all of their limbs independently, as they each have "a mind of their own" so to speak. Studies where researchers have severed a limb of an octopus (they can grow back calm down) have shown that the limbs not only move on their own, but will seize any item it "perceives" as food. This is similar to our reflex to drop anything which is too hot to avoid burning ourselves.
All in all Cephalopods are some of the most intelligent species on the planet ranking up there with dogs, mice, and even the great apes in some areas. Not bad for animals that are cousins with the clam. So I will leave you with two great videos of some True Facts About The Octopus and Cuttlefish courtesy of zefrank1 on Youtube.
GHOSTS ARE REAL! I'm kidding obviously, but seriously how adorable is that? Just when you thought baby turtles couldn't be cuter. But what's the story behind this crazy white turtle? Well first off it's not alone.
Various albino animals.
All of these animals are affected by a congenital condition known as albinism characterized by a reduction or lack of pigment in the skin, hair, scales, etc. as well as pink/blue eyes. Albinism is also found in humans and less commonly in plants where the chlorophyll in the plants is reduced. This negatively affects the plant's ability to photosynthesize which leads to reduced survivability. Albino animals also suffer from their reduced pigment as it can negatively affect their ability to camouflage, or reduce their protection from UV radiation. There have also been studies showing that albino animals have poor eyesight and hearing as well as reduced reproductive viability.
Now while albino animals are strange and eye-catching there is another pigment affecting condition that often gets overlooked. Did you know that these two animals are actually the same species?
Black "Panther" and Jaguar (Panthera onca)
The black panther, as it is commonly called, is actually a title used to describe any of the Panthera species affected by a condition known as melanism.
Top Row: Melanistic and normal jaguar (Panthera onca); Bottom Row: Normal and melanistic leopard (Panthera pardus)
Melanism is the opposite of albinism. While the latter is a condition resulting in the absence of pigment in the skin, hair, etc. the former is a condition which increases the amount of pigment produced. Additionally while albinism has several negative impacts, as described above, melanism is more commonly a beneficial condition. The darker pigmentation can grant greater camouflage capabilities to both predators and prey is many environments, especially at night. Melanism has also been linked to disease resistance in felines; with darker individuals appearing at higher latitudes and in environments where they would be disadvantaged camouflage-wise due to their ability to shake off viruses better than their "normal" coated cousins. Finally there is a wide range of species affected by melanism, from snakes, cats, squirrels, canines, and insects.
Various melanistic animals.
The incidences of this condition in insects are most famously linked to increased pollution from industrial development. For example the peppered moth, Biston betularia, was originally white which camouflaged it against the light colored lichen on the trees. However, with the rise of air pollution in the UK following the industrial revolution the lichen began to die off exposing the dark bark of the trees. This lead to a rise in melanism in the moths as the lighter colored individuals became more obvious to predators.
Peppered moth (Biston betularia) normal and melanistic varieties
Clip from Hitchhiker's Guide to the Galaxy tv series.
Words of wisdom from the late, great Douglas Adams. One of the identifiers, and markers of intelligence in a species is the use of tools. For a long time humanity assumed that it was the sole species to possess this trait. However, the creation and use of tools is a trait that has been documented in numerous species throughout the years. Here we shall discuss as many of them as I feel like typing about.
1. Primates
Ok this one is a bit of a cheat because so many of our closest genetic relatives have displayed a talent for tool creation and usage. So I'm going to briefly touch on several species of primates in no particular order.
First off is the most obvious, Chimpanzees (Pan troglodytes). Chimps are one of our closest genetic relatives, along with Bonobos (Pan paniscus), sharing approximately 98.7% of our genetic code.
From Left: Chimpanzees, Human, Bonobos. Johnny Depp is 98.7% genetically identical to the animals on either side of him.
Chimps and bonobos have been documented crafting and using tools in the wild, but both species have a much higher tool usage rate when held in captivity. Tool usage in these species is widely varied with tools being developed to hunt, scavenge, collect honey and water, crush and chop fruits, nuts and vegetables, and for personal grooming.
Chimps using tools to fish out insects.
Another great ape species which utilizes branches and leaves as a remarkable variety of tools for a multitude of jobs is the Orangutan (Pongo pygmaeus and Pongo abelii). Orangutans have been observed to use tools for many functions similar to chimps and bonobos. They craft hunting and gathering tools, use leaves as gloves to grab thorny branches, and use leaves as napkins. They have even been shown to utilize leaves as megaphones, possibly to make themselves seem larger and more threatening to predators. However, they have also shown a trait that you might think is a uniquely human idea. They have been observed using tools to masturbate. Yeah you read that right. Orangutans fashion tools to help them "get off", and it's been seen in both male and female orangs. While this is certainly the most eye grabbing trait, orangs have also shown a remarkable ability to "ape" (hehehe) human tool use. In the wild orangutans have been observed copying humans spear fishing, and in captivity they have been taught to craft stone hand axes.
Orangutan attempting to spear fish.
Finally among the non-ape primate species the most notable are the capuchin monkeys. Capuchins are part of the new-world monkey subfamily Cebinae, and are split into two genuses, Cebus and Sapajus. Capuchins of both genus have shown a remarkable propensity towards stone tool use. They have been documented using a stone "hammer and anvil" to crush and crack open nuts, fruits and even oysters. However, this is not some innate ability of these monkeys. It can take up to 8 years for Capuchins to master the skills required to use these tools.
Clip from BBC Earth documentary showing Capuchin monkeys cracking
nuts. Narrated by the brilliant Sir David Attenborough.
Capuchins have also shown ingenuity by using stone tools to dig up roots and tubers, and "milking" the secretions of certain arthropods to use as insecticides.
2. Elephants
There are three extant species of elephant, the Asian elephant (Elephas maximus), African bush elephant (Loxodonta africana), and African forest elephants (Loxodonta cyclotis). While these species are famed for their "infallible" memories and are considered among the most intelligent species on the planet, they are not often thought of as tool users. They make up for their lack of opposable digits through the use of their incredibly dexterous trunks. Elephants have been seen choosing, stripping and shaping sticks and branches for a variety of purposes. They create fly swatters, back scratchers, and toe cleaners. They have also shown foresight in their tool creation. Elephants have been observed digging holes which fill with water, then filling the hole with a wad of chewed bark to absorb the water, and covering the hole over with sand to prevent evaporation. This creates a cache of water for the elephant should it return later and need a drink. Elephants have also shown the ingenuity to use large rocks to crush electric fences, either shorting them out or breaking a hole for the elephant to walk through. In captivity Asian elephants will also use boxes in their enclosure as stepping stones to reach food placed purposefully out of reach.
Elephant chews stick to create tool for scratching.
3. Sea Otters!
I had to include this one. As you may have noticed from the background and the title of my blog I have a weak spot for otters. Now tool use is fairly uncommon in the animal kingdom, while it may not appear so from this blog so far, but it is even more unusual in the marine environment. Sea otters (Enhydra lutris) however, are one of the few species with documented tool use capabilities.
Sea Otter using rock on its belly to smash its prey.
I'm sure we're all familiar with the images and videos of sea otters holding the clam, or urchin on their belly and smashing it with a rock to open it. It turns out that sea otters also use rocks to remove their food from the sea bed and rocks it clings to. Otters hunting abalone (a type of marine snail) will often use rocks to bash the snail in an attempt to prize it from the rocks it is attached too. This is much harder than it sounds as the snails can grip the rock with a force equal to 4,000x its own body weight!
Once the otter has prized the snail from the rock (usually requiring several dives to achieve this) it must then break through the snail's hard shell. Recently a researcher from Monterey Bay Aquarium, Jessica Fujii, reported that her team had found that the rate of tool use in otters varies by location. Sea otters down south, off the California coast showed a much higher rate of tool use than those observed in Alaskan waters. Fujii said that this is due to the dominant prey species for these different populations of otters. While urchins are spiny and tough looking, they are actually much easier to break open than the abalone that otters hunt further south. This explains why Alaskan otters showed tool use while eating ~1% of the time compared with the ~16% usage rate by southern otters.
Sea otter using rock to smash open clams.
4. Dolphins
Finally we have come full circle. Here we find the species many consider to be the second most intelligent on the planet, the bottlenose dolphin (Tursiops truncatus). Dolphins are similar to elephants in that while the intelligence is much lauded, they are not considered prime examples of tool using species. However, dolphins have been observed using sponges to protect their rostrum as they hunt for fish along the sea floor. Genetic studies performed on dolphins in Shark Bay, Australia (where this behaviour has been documented) show that it stems from a single matriline (female lineage) with mother's apparently teaching the skill to their daughters. There are also reports of dolphins in this area using conch shells to scoop prey off the bottom making them easier for the dolphins to eat. Dolphins have, like Orangutans, also been documented masturbating in the wild. While perhaps not technically "tool use" a video does exist showing a river dolphin "using" a headless fish.
Bottlenose dolphins in Shark Bay using sponges to protect them while hunting.
Well that's all I have for this blog, thanks for checking it out. I hope you enjoyed the pictures and videos. Come back again soon, and check me out on The Imposter Podcast, run by a good friend of mine, Amir Fogel. Anyway thanks for stopping by!
