The Reptile and the Mammal Within

Pages: 38-39
Year: 2015
Dr. Ida Rolf Institute

Structural Integration – Vol. 43 – Nº 3

Volume: 43

Three and a half billion years ago, life began in the oceans. A pond scum called cyanobacteria started to capture energy from the sun and spit out oxygen. Then, 1.85 billion years ago, oxygen levels were high enough to cause an increase  of several magnitudes of complexity in living organisms. Eventually the ‘Cambrian explosion’ occurred, where oxygen became so plentiful it led to the development of fish, reptiles, birds, amphibians, mammals, and eventually humans.

Mammals developed structures to take advantage of the increased oxygen, and we can help our clients take advantage of those structures. Some researchers believe that our emotions are a byproduct of all the equipment we needed on our journey from reptiles to mammals. Our mammalian hypothalamus makes a good case for that argument. In mammals, it has seven functions: emotions, autonomic control, thirst, food, endocrine function, sleep, and temperature regulation. Reptiles do have a hypothalamus, but it is primarily concerned with mating and territoriality.

Let’s talk about snakes. Snakes don’t smile. They lay eggs and leave them. They don’t hunt in packs. They don’t play. They are either binging or starving – one rat and they are good for several weeks. They sleep much of the time. They have no legs (but some species do have rudimentary ilia that present as appendages that male snakes use to grab females during mating). They have only one functional lung and no diaphragm. Snakes are cold-blooded; this means they are primarily parasympathetic in nature, slow to move and digest. They have to disable their parasympathetic nervous systems and ramp up their sympathetic systems to hunt and mate. They don’t have as much ‘equipment’ to maintain because temperature control is ‘outsourced’ to the environment. Mammals have ‘insourced’ temperature control, so they must have insulation and eat regularly, and are capable of massive amounts of metabolic output.

Despite the fact that the evolutionary gulf between  reptiles  and  mammals  is huge, humans include both respiratory systems. Snakes breathe (and at times digest) with their intercostal muscles – which, like ours, are enervated by the individual nerve from that spinal level. In humans, the diaphragm is our primary muscle of respiration.  It has two enervations: motor function is supplied by the phrenic nerve, originating at C4, and sensory enervation comes from cranial nerve 10, our friend the vagus. The vagus nerve has more than one origin, the dorsal motor nucleus (the reptile one) and the nucleus ambiguous (the mammalian one).

What does this mean? If someone breathes primarily with his intercostals and accessory muscles, he breathes like a snake. Breathing like a snake, you won’t have much energy, and you can’t supply your body with the oxygen needed to move or feel, so emotions will be blunted Some either binge or forget to eat. Breathing like a snake, you will have trouble regulating your temperature. Doesn’t this sound like depression? And since the mechanism of respiration is one evolutionary difference between reptiles and mammals, shouldn’t breathing well – in a mammalian way – potentially have a beneficial impact on mood?

Towards that end, my First-Hour sessions of the Ten Series always include mindfulness regarding breath. Recently, I have added  a piece about our ‘container’, and it goes something like this:

Your diaphragm is your primary breathing muscle. It attaches at the back of your body around L1 [I put  my hand there for reference] and also attaches to the lower ribs. When you breathe, the diaphragm drops, and the rib cage expands three-dimensionally [with the client supine: head to toe, ceiling to floor, and wall to wall]. And the sensation of air in your body goes all the way from your nose to your pelvic floor [once again, I use touch to draw attention towards those places in the client’s body]. Can you, with your eyes closed, feel the distance from your nose to your pelvic floor? [I give some time to explore this.] You don’t have to tell me in inches, but let me know if you feel too long, too short, or just right.

Many people will be able to talk about their perceived felt sense of their trunks, but some people will need more explanation. Most people overthink this part and look for some kind of problem. It’s wonderful if they say with surprise, “My legs feel really far away,” or “Wow – there is nothing between my nipples and my hips” (these are actual client comments).

I tell them something like:

People frequently have these types of sensations, but have never noticed them because nobody has ever asked them. Now that you know about these sensations, they are easy to feel and to change. The only way a body knows how to move is from the sensory feedback  it receives from its muscles, tendons, ligaments, and joints. This type of unusual sensory information will influence how the body moves, and this is very likely one cause of your problem at your [insert body part].

Before we go about adjusting these sensations, let’s look at your depth and width. Are you too shallow, too deep, or just right? Are you too wide, too narrow, or just right?

This exploration gets clients really engaged and curious about perception, and, for most, it’s a completely new way to pay attention. I teach pelvic rolls if the client feels he is too long – that gets proprioception through his hip joints and helps him feel his ‘push’. If he feels too short, I use SARA (sacral ambulatory and respiratory axes; see Drummond 2014). If he feels too narrow or too wide, I continue on with my old faithful tool from Mary Bond’s book, Balancing Your Body, some variation on the Structural Breathing Awareness script (Bond 1993, 34- 36). For someone who feels too wide, I will also stand at the head of the supine client, place one hand on each serratus anterior, and compress during ‘inhale’ and ‘exhale’.

After applying various tools, we go back and see what the client’s perception of his body is like now, and frequently this has changed.

To quote Ida Rolf (1989, 27), “We seek to create a whole that is greater than the sum of its parts. We are searching for a method to foster the emergence of a man who can enjoy a human use of his human being.”

One of the ways Rolfers can support this process is to understand the biomechanics, evolution, enervation, and significance of diaphragmatic breathing, and tools for its transformation.

Barbara Drummond is a physical therapist and a Certified Advanced Rolfer working and living in Oak Park, Illinois. She also incorporates her Hakomi training and an interest in developmental neurology into her work.


Bond,  M.  1993.  Balancing  Your Body.

Rochester, Vermont: Healing Arts Press.

Drummond, B. 2014 Jun. “The  Center of Rolfing SI.” Structural Integration: The Journal of the Rolf Institute® 42(1):43-44.

Rolf, I. 1989. Rolfing. Rochester, Vermont: Healing Arts Press.


The Reptile and the Mammal Within[:]

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