Ants: the incredible heavy-lifting champions
Now, I’m far from being an entomologist, but the diversity of designs in the insect world and their astounding capabilities have always amazed me. Recently, I stood outside in a friend’s driveway watching what struck me as both a funny sight to see, yet truly incredible: a tiny little black ant hauling a dead worm at least 20 times its own size across the driveway to the anthill on the other side. How can such a small insect haul such a comparatively large prize? Also, how much weight can an ant carry?
A recent study on the structure and mechanics of the ant neck joint showed that the neck joint of the ant species Formica exsectoides (Allegheny mound ant) can withstand up to approximately 5,000 times the ant's own weight, far exceeding even the research team’s own estimates of 1,000 times.1
The research team from the Ohio State University arrived at these results when they glued refrigerated ants facedown in a specially designed centrifuge2 that measured the force necessary to deform the neck, with the eventual rupture of the head from the body. (Insects don’t have the brain complexity required to register ‘pain’, let alone when anesthetized by freezing.) The researchers then studied the Allegheny mound ant’s neck joint upon taking it apart. As Carlos Castro,3 one of the authors, explained, “As you would in any engineering system, if you want to understand how something works, you take it apart.”4
In studying the neck structures, the ants were x-rayed using micro-computed tomography (micro-CT)5 machines. These scans revealed “the soft tissue structure of the neck and its connection to the hard exoskeleton of the head and body,”4 and electron microscopy images showed that “each part of the head-neckchest joint was covered in a different texture, with structures that looked like bumps or hairs extending from different locations.”4 The research team thinks that these structures might play some kind of mechanical role, possibly in the regulation of how the soft tissue and the hard exoskeleton come together, or perhaps in creating friction, or in bracing the moving parts of the neck joint against one another.4
The research news article posted by the Ohio State Universtiy stated that “Another key feature of the design seems to be the interface between the soft material of the neck and the hard material of the head. Such transitions usually create large stress concentrations, but ants have a graded and gradual transition between materials that gives enhanced performance—another design feature that could prove useful in man-made designs.”4
According to Nature World News, “the researchers said they hope that their understanding of the mechanics of the ant’s anatomy and its ability to withstand force will be of use in future robotics designs.”6 There are innumerable research projects around the world that have led to scientists wanting to mimic the designs in nature in incorporating them into their own technology.7 This is not surprising as man-made technologies haven’t even come close to the designs we see in the natural world.
It’s astounding how even the smallest creatures can accomplish some of the most amazing feats. However, this is part of the well-known ‘square-cube law’ first discovered by Galileo. That is, strength of both muscle and skeleton depends on the cross-sectional area, which is proportional to the square of the length. But mass is proportional to the cube of the length. Since ants are so small, they are also light, so their muscles don’t need to support much of their own weight, so can be used to carry much more outside weight. But this could not be scaled up to human sizes and beyond, because they would collapse under their own weight (despite science fiction movies like Them! ).8
All the same, such amazing designs as the ant’s strength surely testify of an intelligent designer. Unfortunately, the authors of the study gave the usual unwarranted credit to evolution for the ant’s incredible design features. If the researchers were to take off their evolutionist ‘glasses’ for a moment, they would see the ant’s strength for what it truly is: an incredible design feature by an even more incredible designer.
References and notes
- Nguyen, V., Lilly, B., and Castro, C., The exoskeletal structure and tensile loading behavior of an ant neck joint, Journal of Biomechanics 47(2):497–504, 22 January 2014. Return to text.
- A centrifuge is a machine that spins very fast, so applies an apparent ‘centrifugal force’ outwards from the axis, much as you feel when you’re in a car making a very sharp turn. Return to text.
- Castro is the assistant professor of mechanical and aerospace engineering at the Ohio State University. Return to text.
- Gorder, P.F., With their amazing necks, ants don’t need “high hopes” to do heavy lifting: Ants can lift up to 5,000 times their own body weight, new study suggests, researchnews.osu.edu, 10 February 2014. Return to text.
- Micro-computed tomography is 3D x-ray imaging that is on a smaller scale andworks with a higher resolution than hospital CT scans. Return to text.
- Foley, J.A., Ants can support 5,000 times their body weight before losing their heads, natureworldnews.com, 10 February 2014. Return to text.
- Catchpoole, D., Robot designers want to copy the hummingbird, Creation 36(3):19, 2014. See also creation.com/biomimetics. Return to text.
- Similarly, the square-cube law rules out giant humans many times taller than average people today. See Doyle, S. and Wieland, C., The ‘giant footprint’ of South Africa: Firewalking giant or fortuitous weathering? creation.com/giantfootprint, 14 January 2012. Return to text.