Sunday, November 20, 2016

The alleged increase in two-headed sharks

Why So Many Two-Headed Sharks?

Formerly the subject of horror movies and surreal art, real life two headed sharks have been appearing in the science media over the last few years.

A recent National Geographic article asks the question why have so many two headed sharks been reported in recent years? While there is not firm answer to this question, mutations perhaps caused by disease or toxins, and inbreeding are suggested as causes.

My own suggestion would be that the frequency of occurrence may not have changed at all. Recent publicity may have increased the chances of fishermen looking for, and reporting, two-headed finds. (As adult specimens have never been found, the location of specimens requires close examination of pregnant females or eggs.) This would explain why reports of this phenomena cluster together in time. One cluster around the late 1930s and one in the current era.

It should also be noted that while the media reports are closely clustered, the collection dates for the samples are spread over a wider timescale.
 Rather than being a purely new occurence, two headed shark reports can be found going back centuries. Vincenzo de Romita, for example, is said to have collected a specimen in Italy in 1876. He remarked that such a specimen was "a not common monstrosity", but this suggests it was rare and sought after by natural historians, rather than unheard of.


Below is a list of the of the examples I can locate. If you know of more examples please let me know!

2016 (1)

2013 (1)

2008 (1)

  • Small tail shark specimen (Carcharhinus porosus) from Columbia. Muñoz‐Osorio, L. A., Mejía‐Falla, P. A., & Navia, A. F. (2013). First record of a bicephalic embryo of smalltail shark Carcharhinus porosus. Journal of fish biology, 82(5), 1753-1757.

2000 (3)

  • Two specimens of Rhizoprionodon porosus found in the water of Brazil.Zaera, D., & Johnsen, E. (2011). Foetal deformities in a smooth-hound shark, Mustelus mustelus, from an oil exploited area in Angola. Cybium, 35(3), 231-236.
  • Two-headed blue shark (Prionace glauca).Ferreira, L. A., Ferreira, T. G. A., & Amorim, A. F. (2002). Embryo anomaly of blue shark, Prionace glauca (Linnaeus, 1758) Carcharhinidae, Carcharhiniformes. III Reuniao da Sociedade Brasileira para Estudo em Elasmobraˆnquios SBEEL. Caderno de resumos, 38-39.

1990 (2)

  • An example of smalleye smooth-hound (Mustelus higmani) and  blue shark (Prionace glauca) from the Caribbean sea. Drinan, D. P., Galindo, H. M., Loher, T., & Hauser, L. (2016). Subtle genetic population structure in Pacific halibut Hippoglossus stenolepis. Journal of Fish Biology.

1981 (4)

  • Four specimens of blue shark (Prionace glauca) found in Japan.
    Goto, M., Taniuchi, T., Kuga, N., & Iwata, M. (1981). Four dicephalous specimens of the blue shark, Prionace glauca, from Japan. Japanese Journal of Ichthyology (Japan).

1938 (1)

1934 (2)

  • Two preserved examples of two-headed tope sharks (Galeorhinus galeus) were found in a private collection.  Delpiani, S. M., Deli Antoni, M. Y., Barbini, S. A., & Figueroa, D. E. (2011). First record of a dicephalic specimen of tope Galeorhinus galeus (Elasmobranchii: Triakidae). Journal of fish biology, 78(3), 941-944.

1876 (1)

1642 (1)

  • A two-headed shark reportedly from the river Nile. Possibly apocryphal? Gudger, E. W. (1929). An Unusually Large (53 Mm.) Two-headed Brook Trout, Salmo Fontinalis. American Museum of Natural History.

Tuesday, November 15, 2016

Saturday, October 1, 2016

Thrift StoreSaturday--it's still all about animals

Hand-painted kitten for Halloween decor at the office
Austrian moose--found by Sandi but she let me have it because I do love the cervids
A picture frame for a portrait of my significant puppies
And some golden letters to sign off with.....

Sunday, September 4, 2016

Cartoon: Our New Collie Overlords

There's nothing wrong with being happy

I recently read the Oatmeal cartoon: How to be Perfectly Unhappy.  And about 10 years ago I probably would have identified strongly with it.  But not today, especially the part at the end where the cartoonist throws doubt on whether anybody is habitually happy.

The  things is, people are all different.  Not just different from each other, but also different across time.  In fact the good news is, that with age, people tend to get happier. That has certainly been true for me. Most of the time I am probably in a sort of vague relaxed mode and I am periodically neurotic, stressed, or melancholic, but on a regular basis and for long periods--yes, I am happy.

Today I paid $115 for a workman to tell me my 38 yer old AC/Heater combi unit has blown a fuse so old they don't even carry it, with unknown serious wire damage, so that it needs to be turned off and probably replaced--no doubt at great expense.

How do I feel?  I feel happy.

Today my dog jumped out the window, ran off to chase a rabbit, vanished for about 10 minutes and reappeared bleeding profusely.

How do I feel?  I feel happy.

I don't feel happy anywhere near all the time, but I do feel happy a lot.  That is not some kind of bragging; that is just the truth.  I probably feel happy a lot because my environment is favorable.  I earn an adequate income in a stable job surrounded by wonderful people.  I own about 5% of my own home and surround myself with things I like.

I never became a tenured professor, I never did the family-and-kids thing, I live a lot further from my Mum than I would like.  I experience day-to-day  annoyances like most people.  Broken appliances I can't afford to replace, disobedient dogs, Chicago weather.

Much of the happiness in my life is the product of happenstance, and I am grateful for it.  But when I am confronted with messages that say personal happiness is so rare that its very existence is questionable? No. Just no.  There is nothing wrong with having your emotional thermostat set in another position. But equally...

I am happy. And there is nothing wrong with that.

Wednesday, August 31, 2016

Whistle Ad WTF

Whistle is actually a good product but... um, "keep your pet safe" by having them lean out the window of a (moving?) vehicle alongside a child, with neither of them wearing restraints.

Not so much.

GPS tracking is great, but there are some more basic things you can do to look after your dog.

Sunday, August 14, 2016

PetSmart need to do better by Betta fish

Petsmart is currently promoting the endless possibilities of putting a male betta fish in a one gallon bowl with a plastic plant. Of course one gallon is a sweet deal when they recommend a minimum tank size od one quart, one quarter gallon, .95 of a liter.  Dude.

This means that Petsmart recommends keeping an animal they state has a maximum size of 2.5 inches in a volume of water that could be held in a cube with sides of 2.44 inches. Your fish would be living in the same amount of liquid MacDonald's serves as a beverage (their 32 ounce cup).

It is time for pet stores to mandate an absolute minimum of one gallon, with temperature regulation and a source of water movement and/or filtration. When fish are friends they deserve enough room to turn around in, at the very least.

Oh and that 'build your bowl', set should also come with food, de-chlorinator, and an animal care guide. That does not go without saying.

Thursday, July 28, 2016


Someone actually mad a product you are meant to consume, and called it Soylent.

Are Millennials too young to know the cannibalistic resonance, or just too hip to care?  I may be officially old now, if this is meant to be ironic in some way.

Thursday, June 16, 2016

Breed Specific Legislation and Greyhounds

Most discussion of breed specific Legislation and dogs centers on the banning of the pit bull type in various jurisdictions. Sometimes a grab bag or other "big scary dogs" or breeds sometimes used in fighting might be included. But one interesting variation is Victoria in Australia where anyone walking they greyhound in public must have it leashed and muzzled at all times.

"27. Restraint of greyhounds (1) If a greyhound is outside the premises of its owner and is not— (a) muzzled in a manner which is sufficient to prevent it causing injury by biting; and (b) under the effective control of some person by means of a chain, cord or leash— the owner of that greyhound and any person for the time being in charge of the greyhound are each guilty of an offence and liable, upon conviction, to a penalty of not more than 3 penalty units for a first offence and 5 penalty units for a second or subsequent offence"

If any of you are familiar with greyhound, you will know they are, on average, no more dangerous than any dog of similar size and conformation.  So what this regulation, which endures even after considerable lobbying to remove it, shows is that breed specific bans and limitations become established in a very specific cultural context--but once in place they are very resistant to change.

Recent revisions to the law exempt dogs adopted from a certain adoption program, who are tested, and marked with a green collar.  But this persists in representing any other greyhound from any other source as an especially dangerous dog that may never appear in publish off leash (even in a dog park) or unmuzzled.

As an owner of two greyhounds I find this gives me a sudden and very clear insight into how the average owner of a pit bull type must feel.  Because at one time people training greyhounds on public lands allowed their dogs to bother and sometimes attack people, the rights of the entire breed were curtailed. But the problem was never innately connected to the breed, only the irresponsible choices of their owners. And greyhounds in Victoria are, to this very day, subject to discomfort and unreasonable restrictions as a result.

Which is not to say that greyhound owners in other places do not frequently choose to not let their dog off leash, or to use a muzzle when they deem it necessary, but they do so based on the specific situation and the specific dog just like everyone else.  Which, in my opinion, is how it should be.  For all breeds.

Friday, June 3, 2016

Mosaic Fish

Thift store wooden fish, broken china, Mosaic Mercantile brand adhesive and grout. The back is plain white but I could put a different design on the other side.


Sunday, April 17, 2016

Famous Pet Rats: Roosevelt's Jonathon

We often hear about presidents dogs, or even horses, but what about rats? I came across this in a 1922 Saturday Evening Post:

"We went across the hall from the old cabinet room into the nursery, where there were two or three little beds. Roosevelt went into a corner and brought out a big piebald rat, with a tail some six or eight inches long. He put the animal on his shoulder ... he offered to let me hold Jonathan, but I declined!"

The reporter Mr. Kohlsaat \was not very comfortable around rats, but Theodore Roosevelt clearly was.

Tuesday, April 5, 2016

Back to the Future with Environmental Enrichment

In many areas the story of the animal sciences is one of ongoing improvement.  Whether it is slow and incremental or in fits and starts, we learn to do better.  But when it comes to designing environments that suit the psychology of animals ("environmental enrichment") I think we would gain a lot by going back to some of our earliest efforts.
Take for example this dog room photograph from the annual report of the Animal Rescue League from 1907.  I am sure it might have had some potential disadvantages in the areas of safety and hygiene, but in terms of psychology and behavior it ticks all the important boxes.  Conspecific social contact: check. Room to move freely: check. Comfortable and secure resting area: check. Source of natural light and fresh air: check.

In many ways this facility from over a century ago greatly exceeds the minimum standards required, and actual conditions achieved, within a great many dog-housing facilities today.  Some of it is because of the pressures of the modern world in terms of security and disease control... but it goes to show, there might be as many good ideas in our history as our gleaming scientific data of the future.  After all, what a familiar domesticated animal like dog needs is often more a matter of common sense than objective data. What differs is our willingness and ability to properly provide for those needs.

From this same report, consider the bright airy space offered to convalescing cats. Compare this to the average quarantine or treatment room.  If I was a cat I know which one I would prefer.

Wednesday, February 3, 2016

Dog Seat Belts

Steve Baker -- this traffic is for the dogs (Flikr)
There are two reasons to restrain a dog when it is riding inside a car or other vehicle.  One is that the dogs movement (normally or during an accident) could be distracting or harmful for people, the other is that during a sudden stop or accident the dog could be injuried by falling or flying around inside the cab.

One thing to realise, however, is that the current products being sold as "dog seat belts" are not subject to any real performance testing, and when tested many show catastrophic failures. That is to say, they break when subjected to a sudden force. Most manufacturers report that their products pass some kind of "crash test", but these are whatever the maunfacturer deemed sufficient, not an independent test against empirical standards.

The only brand to acceptably restrain the dog on comparsion testing by the Center for Pet Safety (Subaru) was the Sleepypod Clickit Utility (not an affiliate link). But consideration should also be given to how the design of the harness and point of attachment of the tether can cause more serious injuries ot the dog than of the were unrestrained even when the product does successfully restrain the dog's motion.

Currently most canine vehicle restraints are not tested for either their effectiveness or their actual safety for the dog, and use of properly anchored travel crate may be safer.

  • Zeleny, M., and K. Grusova. "A car accident involving a restrained dog within the vehicle: a case report." Veterinarni Medicina 60, no. 7 (2015): 399-402.

Wednesday, January 13, 2016

Dear Journalist....

"The specimen was sent for testing in a London laboratory, where it was found to be a young common weasel. It was possible the rodent was picked up during harvesting."--Stuff

"An evolutionary tree of mammals" by Graphodatsky et al. - Graphodatsky, Alexander S; Trifonov, Vladimir A; Stanyon, Roscoe (2011).