EVOLUTION
The
Sawfish family is one of the more unusual-looking fish families,
containing species that look like the offspring of a shark and a
chainsaw. Despite their similar appearance to sharks, they're actually a
family of rays (though the sawsharks, an order of sharks, has
independently evolved a similar "saw"). They can reach impressive sizes,
sometimes more than 5m (16 feet), and a metre of that can
be saw.
The saw (or rostrum) is an elongated piece of cartilage extended from
the skull. When sawfish are born, the denticles - the teeth-like points
of the saw - are very small, preventing injury to the mother, but they
grow continually throughout life. Sawfish have been observed scraping
their denticles on the ocean floor, seemingly to sharpen them.
The rostrum is an incredible tool. To catch prey they use powerful
slashing blows, impaling fish or even cutting them in two. However
before they can attack prey they have to find it, and here sawfish use
their rostrum too. Like sharks and rays, they can detect electrical
fields living fish produce. "I like to call it an antenna and a weapon,
because that's what it is - it helps them to find the prey, but then
also to kill it," said Barbara Wueringer (University of Queensland), a
sensory neurobiologist who has previously worked with them.
Sadly, sawfish are very endangered. Their rostra making them vulnerable
to getting tangled in nets and their populations have also felt the
influence of habitat loss - a situation exacerbated by their slow growth
and reproduction. Their strange appearance has caused them to become a
target for traditional medicines and illegal souvenirs. Wueringer hopes
we can use sawfish research to find ways to keep them away from fishing
gear, and knowing what electrical fields they can detect and react to is
a big part of that.
Photo credit: Lorenzo Blangiardi (2010).
To read Wueringer and her team's paper on how sawfish use their rostra, click here: http://bit.ly/SDQ4te
http://
http://
http://www.bbc.co.uk/news/
http://animal.discovery.com/
The
Sawfish family is one of the more unusual-looking fish families,
containing species that look like the offspring of a shark and a
chainsaw. Despite their similar appearance to sharks, they're actually a
family of rays (though the sawsharks, an order of sharks, has
independently evolved a similar "saw"). They can reach impressive sizes,
sometimes more than 5m (16 feet), and a metre of that can
be saw.
The saw (or rostrum) is an elongated piece of cartilage extended from the skull. When sawfish are born, the denticles - the teeth-like points of the saw - are very small, preventing injury to the mother, but they grow continually throughout life. Sawfish have been observed scraping their denticles on the ocean floor, seemingly to sharpen them.
The rostrum is an incredible tool. To catch prey they use powerful slashing blows, impaling fish or even cutting them in two. However before they can attack prey they have to find it, and here sawfish use their rostrum too. Like sharks and rays, they can detect electrical fields living fish produce. "I like to call it an antenna and a weapon, because that's what it is - it helps them to find the prey, but then also to kill it," said Barbara Wueringer (University of Queensland), a sensory neurobiologist who has previously worked with them.
Sadly, sawfish are very endangered. Their rostra making them vulnerable to getting tangled in nets and their populations have also felt the influence of habitat loss - a situation exacerbated by their slow growth and reproduction. Their strange appearance has caused them to become a target for traditional medicines and illegal souvenirs. Wueringer hopes we can use sawfish research to find ways to keep them away from fishing gear, and knowing what electrical fields they can detect and react to is a big part of that.
Photo credit: Lorenzo Blangiardi (2010).
To read Wueringer and her team's paper on how sawfish use their rostra, click here: http://bit.ly/SDQ4te
http://
http://
http://www.bbc.co.uk/news/
http://animal.discovery.com/
The saw (or rostrum) is an elongated piece of cartilage extended from the skull. When sawfish are born, the denticles - the teeth-like points of the saw - are very small, preventing injury to the mother, but they grow continually throughout life. Sawfish have been observed scraping their denticles on the ocean floor, seemingly to sharpen them.
The rostrum is an incredible tool. To catch prey they use powerful slashing blows, impaling fish or even cutting them in two. However before they can attack prey they have to find it, and here sawfish use their rostrum too. Like sharks and rays, they can detect electrical fields living fish produce. "I like to call it an antenna and a weapon, because that's what it is - it helps them to find the prey, but then also to kill it," said Barbara Wueringer (University of Queensland), a sensory neurobiologist who has previously worked with them.
Sadly, sawfish are very endangered. Their rostra making them vulnerable to getting tangled in nets and their populations have also felt the influence of habitat loss - a situation exacerbated by their slow growth and reproduction. Their strange appearance has caused them to become a target for traditional medicines and illegal souvenirs. Wueringer hopes we can use sawfish research to find ways to keep them away from fishing gear, and knowing what electrical fields they can detect and react to is a big part of that.
Photo credit: Lorenzo Blangiardi (2010).
To read Wueringer and her team's paper on how sawfish use their rostra, click here: http://bit.ly/SDQ4te
http://
http://
http://www.bbc.co.uk/news/
http://animal.discovery.com/
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