Women and sharks.. curious

[rainbowtrout22]

So DAN tells us that "it is known" that menstrual blood does not attract "many species" of sharks. There isn't a citation or reference to any data on that.

So question:

how is "it known," did they put samples of it in with some captive sharks??
why would the "small amount" of blood lost pose a problem to a shark, they have amazing sensory capabilities.
"many species"? which ones? which ones *does* it attract, then?


I love sharks and this issue isn't particularly frightful to me, but how can they make that statement, anyone know?

 

[Walter]

From the International Shark Attack File Website.

Menstruation and Sharks
Any bodily fluid probably is attractive to sharks. Blood, in any form, may be at the top of the list. The sharks' ability to detect even minute amounts of blood and scents of other organic material is amazing. Several years ago in the Bahamas I observed juvenile blacktip sharks cruising in waist-deep water. We placed a carcass of a filleted fish in the water and watched as several sharks caught scent of the fish and rapidly made a bee-line to the carcass from long distances away. Obviously no movements from the carcass were involved - only smell was used as the sharks weaved back and forth catching the scent of the small (less than a pound) carcass.

Menstrual blood almost certainly can be detected by a shark, and I'm sure urine can be as well. Do we have positive evidence that it is a factor in shark attack? No, and until some menstruating and non-menstruating divers volunteer to take part in a controlled test we'll never prove it. In my opinion it likely is attractive to sharks in certain situations.

Certainly menstruating women are attractive to such smell-oriented animals as dogs. Sharks, with their extreme olfaction abilities, surely are capable of detecting at similar low levels. Does that mean a menstruating woman is setting herself up? No, but if one is attempting to maximize reduction of risks it is one thing that can be avoided.

As of this writing there have been a male:female ratio of 9.2:1, or more than 90% attacks have occurred on males. This reflects a historic pattern of more males engaged in marine aquatic activities, especially those that put humans most at risk, e.g. surfing, diving, long distance swimming, warfare. It in no way can be attributed to sharks "preferring" males over females. In recent years proportionately more females are being attacked because more females are engaging themselves in riskier, formerly males-only activities.

My advice? Don't worry about it. Lots of women safely dive while menstruating. Although we haven't got solid scientific data on the subject, so far we haven't seen any obvious pattern of increased attacks on menstruating women.


© George H. Burgess, International Shark Attack File
Florida Museum of Natural History, University of Florida

 

[rainbowtrout22]

Interesting note--males also get bitten by snakes far more often, and the bites are to the hands and face (try to pick them up).

I wonder if statistically male divers would have a similar pattern (more likely to engage in risky behavior with the shark).


That was a nice blurb, thanks. I wonder why DAN phrases their advice like that, you would think they have a reason.

 

[ONESPEED]

I recently read a report stating some doubt that human blood attracts sharks at all, I'll try to find it....

 

[drbill]

I've also heard that human blood is not as strong an attractant, at least for some species of sharks. If I remember correctly, the source indicated that some sharks could detect the difference between human and other mammalian blood.

Since I'm a scientist, perhaps I should apply for a grant, get a dozen or so "lady go divers" and test this out with the great white sharks in our waters.

 

[Ayisha]

Since I'm a scientist, perhaps I should apply for a grant, get a dozen or so "lady go divers" and test this out with the great white sharks in our waters.

I suspect that many women test this out quite regularly while diving, perhaps even once a month.

 

[laurelgsc]

Dang if I could guarantee a shark siting I could rent myself out once a month . I know a lot of people who would love to dive with sharks. Bill, I'll volunteer to come out and dive with you. I want to do some kelp diving so bad.

 

[adurso]

I recently read a report stating some doubt that human blood attracts sharks at all, I'll try to find it....

The rationale is that people are not on the shark menu as a rule, therefore evolution focused on things that are on the menu. Anecdotally human blood will engage shark interest, though not to the extent fish blood will.

 

[KateAus]

I was a little nervous when I realised a dive with Grey Nurse Sharks was bad timing. There were over a dozen sharks and the Alpha of the Group took an interest in my male partner over me

I can only speak about my experience with smaller species of sharks, but I find they are generally too timid of us to worry about too much (but of course keeping a healthy level of respect)

You should also think about diving accidents, I'm sure every diver has experienced the od scratch under water which would put you at just as much risk. I'm not basing this on any scientific facts, just the thought process I went through

 

[nshorez]

i submit blood is blood
how much blood gets out of a females wetsuit into the water, vs. say a spearfisherman with 3 dead fish on it, likely is negligable, wouldn't you say
and you actually dont want to attract the tiger sharks here in hawaii
who are the likely ones to come looking, not the reef sharks, during day dives anyway