Analysing the music of Racer Snakes vs Iguanas: how is it telling the story? (Part 1)
We all know the sequence of racer snakes chasing iguanas from the BBC’s Planet Earth 2 is breath-taking (if you haven’t seen it yet, check it out!). It won the ‘Must-see Moment’ BAFTA award in 2017.
But what part is the music playing in this emotional roller-coaster? The director, Liz White, admitted that ‘If you watch it without the music, it hasn’t got anywhere near as much impact,’  (a comment reminiscent of Bernard Herrmann’s claim that Hitchcock only finished his films to 60%, but that his music had ‘to finish it for him’) .
The composers are Jacob Shea and Jasha Klebe (with the main title music by Hans Zimmer), and both have a background in writing for Hollywood cinema. Yet for Jasha Klebe, the iguana scene, with its ‘phenomenal editing’, was ‘a chase scene that beats any Hollywood movie out there’  and for Jacob Shea, this moment was ‘a harrowing, post-apocalyptic chase scene like no other’.
This article is not an exhaustive analysis. Rather, it presents a selection of some of the musical techniques that these composers have used to tell the story of this incredibly exciting and engaging sequence.
With our first glimpse of an emerging hatchling iguana (20 mins 58 seconds into the episode ‘Islands’), David Attenborough is explaining that these hatchlings are ‘vulnerable’. This is accompanied by two long chords – D minor followed by B minor (also the beginning of the TV soundtrack album version).
D minor B minor
Several musical techniques support this word ‘vulnerable’.
– We hear no pulse – there is a sense of waiting, we don’t know what’s going to happen.
– The instrumentation is muted strings, lacking warmth and expression, giving the impression of frailty and tentativeness.
– There is no low bass instrument underpinning these chords, which leaves us feeling unsupported. – The first chord, D minor, is scored in ‘second inversion’ (D/A): instead of having the solid feel of the D as the lowest note, we feel suspended by having the A as the lowest note, giving the impression of being emotionally ungrounded.
– These two chords do not traditionally belong together in the same key. Chord VI in the key of D minor would normally be Bb major, but by choosing B minor the composers introduce a chromatic shift in the top note from F natural to F#, and this leaves us unsure about the overall tonality (what key we’re actually in). The first chord has an air of sadness, but the unsual shift of tonality introduces an element of suspense and impending threat.
The story begins – we are introduced to our ‘vulnerable’ main characters, and the music perfectly paints this scene.
Following the word ‘dangerous’, a low drone begins on the notes D and A (21 mins 17). Why do low drones sound so ominous? Perhaps we have a visceral reaction to low sounds because we associate them with threats such as thunder, or a growl, or earthquakes? John Williams exploits this effect with his shark theme in the film ‘Jaws’. This drone is not static, it is full of evolving sounds; sounds gently moving up and down in loudness and harmonic frequencies, a random throbbing effect that gives the impression of lurking danger, rather than death and desolation.
And then a hit point occurs – almost imperceptible (at 21 mins 30). At the split second the head of a racer snake appears far right of the screen, a quiet mid-range note (A ) enters. A second dissonant note above it (Bb) joins it, followed by another snake. Then a third note (C) is added, along with a third snake. Harsher, clashing notes begin, getting louder, as the snakes are getting closer and closer to the iguana. The story paints these snakes (who no doubt also have to eat) as the terrifying villains.
A sudden deep strike on a bass drum (at 21 mins 45) ushers in the first (of four) ‘action’ sequences, like a jump scare, as the iguana erupts into a sudden run for its life, chased by the snakes. The high-speed ticking sound in high percussion appears to match the speed of the iguana’s footsteps. Our emotional reaction is no doubt based on more associations: this is the classic sound of Hollywood action sequences, even down to the 1,2,3,1,2,3,1,2 pounding rhythms. But there are other associations based on physical human reactions; the fast pulse resembles our own speeding heart-rate during fight or flight; the accented percussion crashes feel random and unpredictable, therefore frightening because we cannot control them.
This unpredictability is enhanced by what feels like an additional two beats inserted after four bars of four beats of this ‘action’ rhythm. This results in a strong downbeat occurring precisely with a new close-up shot (21 mins 53), which also sounds slightly louder, as if we ourselves are simultaneously closer. Closely synchronising music with the images gives a sense of immediacy that the composers wanted, by making the audience feel they are right there with the characters, as they fight about life and death.
The action music pauses as the first iguana reaches safety. But, interestingly, the music tells us that it isn’t reaching the rocks that signifies safety, but gettting his foot down firmly at the top. The pounding rhythms stop not when the iguana first jumps up onto the rocks, but in a slowing sequence marking each steady step to the top.
The iguanas and snakes story is told in five musical sections, each section consisting of tension music followed by sudden action music. (The music just described here was the first section of five). In the next part of this blog, I’ll look at the other sections.
 Royal S. Brown ‘Overtones and Undertones’, page 148.
 Interview – https://www.youtube.com/watch?v=zwO3uRfrzAQ
 Interview – https://www.youtube.com/watch?v=pC-yUSAAiJM