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No. 43
Work wise it is as quiet as it gets at Animal Ark. Meanwhile the rains have come, frogs are breeding and our garden is lush and colourful. We get to see some beautiful winter flowering bushes and trees, which brings me to vision – we, you and I, see things differently to many other animals.

Creatures perceive things in various ways; the colour of plants and trees is lost on my dogs that mostly only see greys. Whilst vision is the primary source of much of our human experiences, with dogs it's more about odour (olfactory stimulus).

Which has got me to wonder a bit about the eye as an organ, the variation in animal vision, and our brains interpretation of just what is out there - beyond the body.

Red eye tree frog. Photo: Animal Ark
The eye is an organ that reacts to light and pressure. As a sense organ our mammalian eye allows us to have vision. We humans only detect red, orange, yellow, green, blue, indigo and violet, the same colours we see in a rainbow. For us that is the visible spectrum.

Many animals perceive the world differently and see light at wavelengths that we simply cannot detect. Some insects like bees and butterflies can see in the ultraviolet wavelength with many flowers showing 'landing stripes' enabling bees for example to hone in to the nectar and pollens.

Some snakes like vipers and pythons have heat pits - special scales that have evolved to 'see' the infrared thermal radiation. This may help them detect prey, avoid a predator and also probably to find a sunny spot to enable them to sunbathe.

Eyes of the Jumping Spider (Phidippus pius). Photo: Opoterser - Wikimedia-commons.

Eagle Owl. Photo: Animal Ark

The world's largest invertebrate also has the world's largest eye. The Colossal Squid Mesonychoteuthis hamiltoni has a pair of 28cm wide eyes. The clear, jelly like lens are 'orange sized' at 5cm diameter.

So rare are these deep-water creatures that these measurements come from the only intact eye ever recovered from a specimen.

The eyes may well get larger as the recovered specimen studied was only 8 metres long and scientists believe these depth dwelling predators may grow to at least 14 metres in length.

Giant squid eye. Photo: Smithsonian Institute, Wikimedia commons
To start with, trust me – any particular object like a flower or fruit, let's say a banana, is not actually yellow - really it isn't.

But because the yellow light waves that hit the banana reflect off it reaching the light sensitive retina at the back of your eye and via your optic nerve sending signals to the brain we interpret what we see as yellow.

Toco Toucan. Photo: Animal Ark
My favourite eyes? Almost without doubt I have always loved the chameleon eye. Although it is not colourful itself, it is encased in a volcano like cone surrounded often by very pretty scales.

Chameleon eyes are almost unique as they swivel independently giving them the ability to see in 2 different directions at the same time.

Colour wise though few match the eagle owl, tree frog or tree viper.

Panther chameleon (Furcifer pardalis). Photo: Tom Junek - Wikimedia commons
Despite studying bacteria for 340 years with microscopes it is only in the last year or so that studies have found that cyanobacteria have a functional resemblance to an eyeball or lens. So watch out, because those bacteria may well be watching you.

Detecting light from dark (seeing) was an important function 2.9 billion years ago, allowing primitive bacteria like cyanobacteria to navigate towards light to enable photosynthesis. One single Synechocystis cell may be 500 billion times smaller than a human eye but it 'sees' and moves towards the light.

Hamelin Pool Stromatolites formed by cyanobacteria. Photo: Allison Coleman - Wikimedia commons
How slime sees image. Source: eLife on
Eyes can come in many shapes, sizes and colours and vary significantly among the animal kingdom. Several animal species have utilised the intimidating aspect of the eye and display fake eyes, otherwise known as eyespots, on their body. It's thought that animals use these false eyes defensively, to ward off predators. Several species of birds, frogs, fish and insects including butterflies have exhibited eyespots of some form. The male peacock has many false eyes on its tail feathers but these are used to attract a female – the more and brighter the eyes the better chance of being selected as a mate.

A common example of an Australian animal with eyespots is the hawk moth caterpillar. There are an estimated 850 hawk moth species worldwide, with 65 species residing in Australia. The hawk moth's larvae, also known as a caterpillar, are typically large and colourful and very edible. Hawk moth larvae otherwise have excellent camouflage but when threatened can raise their body displaying 2 huge eyes on the abdomen with the intention of changing what a potential predator sees from an easy meal into possibly an angry and much larger creature.

I personally found a hawk moth caterpillar several months ago on the gravel near my orchard. When I first saw the larvae, it was a magnificent green colour however, after a few days the colour faded to brown and shortly after that wrapped itself to some leaves with spun silk to form a cocoon. Pupation usually takes place on/in the soil or amongst the leaf litter, so if you find a hawk moth on the ground it's best to leave it alone as it may actually be ready to pupate!

Words by Ziggy at Animal Ark

Hawk moth caterpillar (Hippotion celerio). Photo: Jon Rose

Peacock feather fan. Photo: Pete121 - Wikimedia commons

Reef fish with false eye spot. Photo: Animal Ark

Butterfly wing with eye spots. Photo: Animal Ark

Our most popular pets have very poor colour vision indeed. Cats, dogs, rabbits and many rodents like rats and mice see the world largely in shades of grey along with a little blue and yellow.

To try to understand what animals see scientists need to look at the rods and cones within the eye. Cones are the photoreceptors that help with the perception of colour. Rods are more sensitive to light and dark, shape and movement.

Close up of husky eyes. Photo: Animal Ark
  • Frogs and geckos can see some colours in the dark.
  • Falcons can see a 10cm object at a distance of 1.5km.
  • Several hawks can also keep an object in focus whilst diving at 160km per hour.
  • Dolphins sleep with one eye open.
  • Pigeons see millions of hues and have better colour vision than most animals.
  • Eagles eyesight is an estimated 4 to 8 times stronger than an average human, although the eyes are roughly the same size - they can spot a rabbit 3.2km away.
American Bald Eagle. Photo: Animal Ark
Animal in Focus: Darwin Stick Insect (Eurycnema osiris)
A few months ago, we added two new additions to the Animal Ark family: Twiggy and Leaf. They are Darwin stick insects. Living in Perth you don't tend to see overly large stick insects so it was a pleasant surprise when they arrived, particularly Twiggy, she is huge! A female Darwin stick insect can be on average 30cm long whereas the male is quite a bit smaller and slimmer than the female, with a length of 17cm. Although much smaller, the adult males sure know how to fly!

Darwin stick insects are native to the forests and woodlands across Northern Australia, including the Kimberly in WA and can often be found up in the tree canopy. Each of the 6 legs is well equipped with hooks to stop them blowing away or dropping off. They have incredibly good camouflage and are very difficult to see and or find! Being herbivores they eat foliage but are actually quite picky with what leaves they like to eat. Twiggy and Leaf, love to eat eucalyptus leaves, but have also been known to eat leptospermum, acacia and melaleuca leaves. Foraging on leaves means that these stick insects don't have to go very far for water. Darwin stick insects have adapted to their surroundings and drink the dew or raindrops right off of the leaves. I remember the first time I saw it, being an animal person, it was really fascinating to watch as they lick or slurp up the moisture.

The females have an unusual way of dispersing their eggs. A Darwin stick insect's eggs look very similar to little seeds pods. The female stick insect lays her eggs one at a time, as one emerges from her abdomen it is automatically loaded into a scoop shaped appendage, she then flicks it away to scatter them around the area. This is an amazing event to watch if you ever get the chance. By strewing the eggs around she increases their distribution (and her genes distribution) and when they hatch, they will hopefully find their own tree and habitat. A young/immature stick insect is called a nymph. We have dozens of eggs from Twiggy and Leaf, which will hopefully hatch in a few months time!

Yes she has eyes as well Twiggy our female stick insect.

Words by Ziggy at Animal Ark

Twiggy, a Darwin stick insect (Eurycnema osiris). Photo: Animal Ark

Twiggy the stick insect on hand. Photo: Monica Iseppi / Animal Ark

Upcoming Courses and Events
Venomous Snake Handling Course
DPaW approved for Reptile Relocator's Regulation 17 Licence
Friday 1 September – Malaga, Perth
Friday 15 September - Malaga, Perth
Friday 22 September – Bunbury, WA
Friday 6 October - Malaga, Perth
Tuesday 7 November - Malaga, Perth
Friday 1 December - Malaga, Perth
Friday 15 December - Malaga, Perth

Fauna Handling Course
Friday 25 August – Malaga, Perth
Thursday 31 August – Malaga, Perth - FULL
Monday 6 November – Malaga, Perth

Snake Avoidance Training for Dogs
Saturday 12 August – North Beach, Perth
Saturday 16 September – North Beach, Perth
Saturday 23 September – Bunbury
Sunday 24 September – Bunbury
Thursday 28 September – North Beach, Perth
Saturday 30 September – North Beach, Perth
Sunday 8 October – North Beach, Perth
Saturday 14 October – Perth Hills
Wednesday 18 October – North Beach, Perth
Saturday 21 October – Bunbury
Sunday 22 October – Bunbury
Tuesday 24 October – Augusta / Margaret River
Wednesday 25, Thursday 26 October - Nannup
Saturday 28 October – Mount Barker / Albany
Sunday 26 November – Rockingham

Public Events
Do come along and see us. Bring your family or friends as well.
The Animal Ark Roadshow will be attending the following events:

Sunday 17 September
Celebrate Lake Claremont
Stirling Road, Claremont
Free community event. Contact Town of Claremont for more information.

See our diary for more dates or contact us to book.

Call (08) 9243 3044, SMS 0466 688 188 or email David, Jenny or Ziggy at to book.

Courses held monthly and as required plus on-site and remote site training available.