From Comparative Physiology of Vision

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General Anatomy

Pigs/swine/Sus Scrofa can see 310 degrees around their head, and their binocular vision zone is 35-50 degrees.[1] The general anatomy of swine eyes are grossly similar so primates, and humans. They're good cadavers because its easier to come by than humans and a whole lot cheaper. I'd assume. Because of this, I had a hard time finding articles on swine eye anatomy without the it's focus on humans. However, there are some differences between us and swine. I'll discuss are few of them in the following.

Unique Visual Optics

The iridiocorneal angle (the angle formed between cornea and iris) formed by swine eyes are unique from primates and humans, in that The ligaments spanning from the cilliary msucle to the lens (pecinate ligaments) are denser, The cords composing the inner uveal meshwork of the trabecular structure were even thinner than ours.The trabecular is near the ciliary body attached the cornea, and is responsible for the draining of aqueous humor through the anterior chamber. Heres a link through wikipedia of a picture from Gray's anatomy, of a human eye, you can't see the individual parts of the trabecular structure, but you can at least see where it is. domain.http://upload.wikimedia.org/wikipedia/commons/2/22/Gray870.png

Swine also differ from us because of their; "poorly developed ciliary musculature, and an angular aqueous plexus"[2]

Photo Transduction

The following link has a great diagram/map of phototransduction for pigs (Sus Scrofa) as well as many other animals. http://www.genome.jp/kegg-bin/show_pathway?org_name=ssc&mapno=04744&mapscale=1.0&show_description=show I compared phototransduction of pigs and humans,

Notes from differences between between pig/human Light RGS9 Interracting with rhodopsin after stimulation of light is white in pig and green in human.

GC Protein in the observed right of disk membrane is white in pig and green in human.

NCKX potassium and calcium out/sodium in pump protein is white in pig, green in human.

Dark Same color differences

I clicked on the boxes mentioned above... The white boxes simply weren't links. So its safe to say that, according to the pathways in this diagram, phototransduction is the same in the photoreceptors of both humans and pigs. But thats only in the receptor, the pathways from the optic nerve to the occipital lobe might differ.

Color Vision

Two classes of cones have been observed in swine eyes via Examination with an electroretinogram (ERG). Ideal average maximum photoreceptor response was shown to be lightwaves between 439 nm and 556 nm.[3] This indicates color vision receptor response peaking at light blue and yellowish green.

Motion Detection

Neuronal Processing

Higher Order Visual Perception

Evolutionary Significance


  1. http://animalbehaviour.net/JudithKBlackshaw/JKBlackshawCh3e.pdf
  2. P G McMenamin and R J Steptoe Department of Anatomy and Human Biology, University of Western Australia, Nedlands.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1260535/
  3. Jay Neitz and Gerald H. Jacobs (1989). Spectral sensitivity of cones in an ungulate. Visual Neuroscience, 2 , pp 97-100 doi:10.1017/S0952523800011949 http://journals.cambridge.org/action/displayAbstract;jsessionid=6A4F308F96FCECC269129ABF9CFC1141.journals?fromPage=online&aid=4645368

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