Bengal Cat Eyes

One of the first things noticed on a Bengal head is their eyes.  Eye color, shape and placement all play an integral part of how the overall look of the Bengal is portrayed.  Unfortunately, it’s a feature often overlooked in breeding programs.   Here’s our interpretation here on this blog at Alora Cats:  Texas Bengals and Savannahs.   Read and study TICA’s breed standard on eyes below:

Eyes: Oval, almost round. Large, but not bugged. Set wide apart, back into face, and on slight bias toward base of ear. Eye color independent of coat color except in the lynx points. The more richness and depth of color the better. 

Its wide nose with prominent whisker pads and large oval, almost round eyes in a slightly small head enhance the wild appearance and expressive nocturnal look.

So, why almost round, not just round?  Let’s start with the one end of the spectrum and venture to the other end, oval.  The Bengal breed is based on the small, forest-dwelling cat such as the Asian Leopard Cat (P. b. bengalensis), that average around 9 lbs.  Every feature of an animal has a purpose for survival.  Let’s begin with EYES!

Photo credit: NPR

What’s the first thing you notice with the six photos of above eyes images? Pupil alignment.  Eye shape.  Eye placement.  Eye color.  Each animal has a distinct purpose for each of these features.  Let’s explore why in generality, then more into specifics with the feline species.

According to a study in Science Advances, pupil shape is directly related to a species ecological niche.  Vertical slits are seen in active daytime and nighttime predators whereas horizontal slits are in herbivorous species with eyes on the side of their heads.   Circular pupils are found in animals that chase down their prey, like tigers.

Horizontal pupils extend the view of sight on the ground level by limiting the amount of dazzling light.  This is commonly seen in grazing animals such as sheep, goats, and deer.  Professor Banks from the University of Berkeley explains this theory as follows: “The first key visual requirement for these animals is to detect approaching predators, which usually come from the ground, so they need to see panoramically on the ground with minimal blind spots. The second critical requirement is that once they do detect a predator, they need to see where they are running. They have to see well enough out of the corner of their eye to run quickly and jump over things.”   

Vertical pupils are an asset for ambush predators so that they can accurately gauge the distance to pounce on their prey.   Distance is measured using three mechanisms:   “stereopsis; motion parallax, in which closer objects move farther and faster across our field of vision; and blur, in which objects at different distances are out of focus.”  Motion parallax does not work for predators because it requires head movement, which would give away their position.  So, they use disparity and blur with their vertical pupils.

Another factor that differentiates certain ambush predators is hunting height.  Those that hunt close to the ground, such as small cats, have vertical slits.   Bigger cats such as Tigers and Lions have large round eyes, similar to humans and dogs.  According to a study at the University of Berkeley, “Among the 65 frontal-eyed predators in the study, 44 had vertical pupils, and 82 percent of them had shoulder heights that were less than 16.5 inches (42 cm).”  Vertical pupils allow shorter animals to judge prey from a distance by calculating the depth of field via blur.

Now that we have established a bit of general background information about eyes, prey, and predators, let’s apply the same science on Bengal cats!

There is a ton of variation amongst Bengal cats – especially with eyes.  Color, shape, and placement within the skull are all so different.  What is correct and why?  How does a breeder or judge make the decision one is better than the other?  Some of it is subjective to personal preference, but let’s investigate what is not only best for the breed, but for the predator that naturally exists within the cat.

Eye color is correlated to coat color.  Genetically, Seal Lynx Points will always have blue eyes.  Seal minks and sepias will have aqua to green eyes.  Brown spotted tabbies will have the most variation, green to brown to gold.  In my opinion, eye color is a personal preference in addition what is genetically allowed.  A gold eyed Bengal is no better than a green eyed Bengal.  The best reference of all the color descriptions for cats can be found here:  Uniform Color Description.

So far we’ve covered pupils, eye color and predator vs. prey behaviors in regard to eyes.  The most important and complex issue with Bengal eyes is placement and shape.  It’s actually a very controversial topic among Bengal breeders.  As referenced earlier, TICA’s standard calls for almost round to oval, but this is currently in question for CFA’s standard.  Should it be redefined?  Is TICA’s description too broad?

The Bengal breed allows us to have domestic lap leopards.  Unfortunately, that entails too much variation and interpretation of the breed standard amongst breeders, pet buyers and judges.  One may prefer a single-spotted over a two-toned rosetted cat.  Another may pick a seal lynx point with blues eyes over a gold-eyed brown spotted tabby.  Then there are people that prefer that “wild” looking cat.  Well, eyes play a significant role in that feature!  We have LOTS of examples of our rescues, Bengals, and savannahs for comparison.

Personally, it took me a few years to understand the “wild” look of a Bengal.  My first thought was, “They all look wild, they have spots and stripes!”  Actually, it’s not that simple.  The term nocturnal is used frequently to describe a “wild” looking Bengal.  It’s a legitimate description, but the word itself is difficult to explain to the newbie bystander.  Cats, in general, are nocturnal, carnivorous hunters.  Asian Leopard Cats (ALCs) are even more so because of their smaller size and shy characteristics.  Can you imagine a 9 lb ALC competing with a 600-lb tiger for prey throughout the day?   The logistics of the wild are just fascinating!

So for a night hunter, one’s eyes must be able to detect their prey in the dark.  This is where the nocturnal piece comes in handy.  It’s not natural for a cat to walk up to a bowl of food in the forest, prairie or jungle.  They HUNT!  We rescue many feral cats.  They are a great example of survival of the fittest.  When you rely solely on yourself, you use primal instincts for survival.  The feral communities are comprised of big, smart hunting cats.   They all have keen senses – smell, hearing, sight and awareness of their environment.

Feraleyes

Pictured above are my rescues.  They are very smart, have excellent hearing, eyesight and can withstand winters without blankets, boxes or human touch.  One hardy bunch!  Now that they have been spoiled to death inside the Alora Cats cattery, they have lost some of their survival needs, now they just rely on us for food and water. Let’s examine their eyes.  Notice a commonality?  Not one of them is round!  So, is this the reason for the “almost round” end of the spectrum of the Bengal eye description?  Remember, large round eyes are found in forage predators of the day, such as lions and tigers, not small low-lying cats like the Asian Leopard Cat.

Round eyes are found in domestic breeds such as Persians, Himalayans, and Exotic Shorthairs.  Not exactly breeds we expect to be outside running, jumping and hunting during the late hours. Coincidence?  Look at the examples below.

roundeyes

Notice how the inner and outer curvatures of the eyes are round?  Compare these to the Bengal photos below.  What differences do you observe?  What are the commonalities are seen between the two groups?

bengalEyes.jpg

Pictured above are all Bengals with the exception of the center photo, which is an ALC.  To the right of him is his daughter, an F1.  Regardless, all of them have a half circle pattern to the bottom half with an almost straight angle on the inner edge of the eye. Then there are differences when it comes to the inner eye and top portions.  Again, NONE are round as pictured earlier.  This further supports the “almost round” language that describes the Bengal eye.  Notice the two photos on the bottom row on each end have a rounded effect to the eye.    When I personally view these sort of eyes, I don’t see the “wild” type like I witness in the ALC or other photos.  Notice the similarities between the ALC and the top row of Bengals?  Rounded bottom half with squarish effects on the inner sides.  Definitely not round.  This is the wild look that I personally see in Bengals and ultimately want to breed in our program.  Also, notice how the squarish inner sides of the eyes align with the nose leather.  Coincidence?  No! This is another wild trait in my opinion.  Now check back with the feral collage.  Notice, they have a similar squarish effect to their inner too—not as dramatic, but it still exists.  Pretty cool, eh?

I hope you enjoyed this reading.  It’s all based on my personal experience with breeding Bengals and rescuing the feral community.  If you have any questions or disagree with my opinion, I’m happy to discuss anytime!

 

 

 

 

References:

Martin S. Banks et al. 2015. Why do animal eyes have pupils of different shapes? Science Advances, vol. 1, no. 7, e1500391; doi: 10.1126/sciadv.1500391

Website:  AloraCats

UC Davis places new PRA test on hold

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At AloraCats, we like to stay current with medical and genetic updates regarding bengal and savannah cat breeds.  Progressive Retinal Atrophy is a common genetic trait that causes blindness in the bengal breed.  Below is the latest from the UC Davis Website:  UC Davis PRA Test.

Bengal Progressive Retinal Atrophy (PRA-b)
Temporarily on Hold 4-8 Weeks

The Veterinary Genetics Laboratory has very recent evidence that a small percentage of results for the Bengal Progressive Retinal Atrophy (PRA-b) test reported as PRA/PRA is not accurate. We also believe that N/N and PRA/N results are correct as issued.

As this test is based on cutting-edge research, it was validated on a subset of the cat population. Performing this test on a larger number of cats has likely uncovered additional genetic variation that the current test did not take into account.

Accuracy of our results is paramount, and we are putting a temporary hold on testing of new samples until our investigation is complete. Identification of the issue, new assay design, and validation may take 4 to 8 weeks, and we will begin offering the test again once we are confident in its accuracy and reliability. At that time we will verify every result already issued, and update all of our Bengal clients via email and website.

We hope for your patience during the next few weeks. However, if you would like a refund for Bengal PRA-b testing, please contact us, and we will process that immediately.

This is a situation that can happen with genetic test development, especially with hybrid cats. We will proceed with this testing as soon as possible. We apologize for the inconvenience.

Introduction

Bengal cats have an inherited progressive retinal atrophy similar in presentation and progression to retinitis pigmentosa in humans. Clinical onset can be observed as early as 11 weeks with variable progression of photoreceptor degeneration. In a colony segregating for the disease, terminal retinal degeneration ranged from 60 to 143 weeks. Gradual progression and environment adaptation by affected cats may obscure recognition of the condition by owners. The disease is inherited in an autosomal recessive fashion thus two copies of the defective gene must be present for the disease to manifest and both sexes are equally affected. Carriers, cats with a single copy of the defective gene, exhibit no signs of degeneration. Mating between two carrier cats is expected to produce 25% affected kittens.

Research by Dr. B. Gandolfi in the laboratory of Dr. Leslie Lyons, University of Missouri, identified the mutation associated with PRA-b. The VGL offers a DNA test for PRA-b to assist owners and breeders in identifying affected and carrier cats.

The Bengal PRA DNA test is recommended for the Bengal breed and breeds using Bengal cats in breeding programs.

Procedure for collecting a feline DNA sample

ORDER TEST | PRICE LIST
Allow 2-6 business days for results.

Results reported as:

Test Result Progressive Retinal Atrophy-Persian Derived (PRA-pd)
N/N Normal – no copies of the PRA-b mutation
N/ PRA Carrier – 1 copy of the PRA-b mutation; vision will be normal
PRA/ PRA Affected – 2 copies of the PRA-b mutation; cat will develop clinical signs of Bengal PRA