Images Reveal Spider's Double-Beating Heart

An MRI scan of a tarantula. The heart is in the spider's abdomen, shown here as an elongated yellow region. CREDIT: Gavin Merrifield View full size image

Researchers have recorded the first real-time images of a tarantula's heart beating.

The video, captured with magnetic resonance imaging, or MRI, reveals how blood moves through the tarantula's heart, said study researcher Gavin Merrifield, a University of Edinburgh doctoral candidate.

"In the videos, you can see the blood flowing through the heart, and tantalizingly, it looks as though there might be 'double beating' occurring, a distinct type of contraction which has never been considered before," Merrifield said in a statement.

A still from the MRI video of the tarantula's heart beating.
CREDIT: Gavin Merrifield

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The MRI allowed researchers to measure the spider's heart rate and cardiac output (how much blood it pumps per beat) noninvasively as part of an ongoing study of tarantula biology. [See images of the tarantula's heart]

A sedated tarantula in an MRI machine
CREDIT: Gavin Merrifield

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"One potential practical use of this research is to ascertain the chemical composition of spider venom. Venom has applications in agriculture as a potential natural pesticide," Merrifield said.

"On the more academic side of things, if we can link MRI brain scans with a spider's behavior and combine this with similar data from vertebrates, we may clarify how intelligence evolved."

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