Gator Oscillator: Reading the Alligator's Growing and Shrinking Jaws

The Gator Oscillator is a direct extension of the Alligator — it takes the same three Jaw/Teeth/Lips lines and turns the distance between them into a histogram, so a trader doesn't have to eyeball whether the lines are tangled or fanning out. Bill Williams, who built both indicators as part of the same system, designed the Gator to answer one specific question the Alligator's lines alone make harder to read at a glance: is the alligator's mouth actually opening — is the trend actually accelerating — or has it stopped growing?

How the Gator Oscillator Is Calculated

The Gator plots two histograms in a separate window below the price chart, both derived directly from the Alligator's three lines:

• Upper histogram — the absolute distance between Jaw and Teeth, plotted as positive bars above the zero line.
• Lower histogram — the absolute distance between Teeth and Lips, plotted as negative bars below the zero line.

Each bar is colored based on whether it's larger or smaller than the previous bar: a bar taller than the one before it is growing (the lines are spreading further apart), and a bar shorter than the one before it is shrinking (the lines are converging back together). Because both histograms come directly from the same Jaw/Teeth/Lips values covered in the Alligator lesson, the Gator adds no new inputs of its own — it's a different visualization of information the Alligator already contains, not a separate calculation.

Reading the Gator: Sleeping, Waking, Feeding

• Sleeping — both histograms sit small and close to the zero line, shrinking or barely changing bar to bar. This mirrors the Alligator's tangled lines during a ranging market: the mouth is essentially closed.
• Waking up — both histograms start growing together, bar over bar, as the Alligator's lines begin to separate. This is the "mouth opening" moment Bill Williams built the Gator to flag mechanically.
• Feeding — both histograms are tall and still growing, matching a fully fanned-out Alligator with price riding clear of all three lines. This is the strongest phase of the underlying trend.

The diagram above shows exactly this progression: small, barely-changing bars while price chops sideways through the tangled Alligator, then both histograms growing together as the lines fan out and price breaks into a clean trend.

Entry Conditions

The included custom indicator watches for both histograms growing at the same time — the "waking up" moment — and uses the Alligator's own line order to decide which direction that momentum favors:

• BUY signal — both the upper and lower histograms are growing on the same bar, and the Alligator lines are fanned in bullish order (Lips above Teeth above Jaw).
• SELL signal — both histograms are growing on the same bar, and the lines are fanned in bearish order (Lips below Teeth below Jaw).

Growth alone, without checking the fan direction, only tells you the lines are separating — it says nothing about which way. That's why the alert logic always checks the Alligator's own order at the same bar rather than treating a growing histogram as a signal on its own.

Parameters

Because the Gator is calculated entirely from the Alligator, every parameter it needs is the same one the Alligator uses:

• Jaw Period / Jaw Shift — default 13 / 8, the slowest of the three lines.
• Teeth Period / Teeth Shift — default 8 / 5, the medium-speed line.
• Lips Period / Lips Shift — default 5 / 3, the fastest line and the one most responsible for early histogram growth.
• MA Method — default SMMA, matching Bill Williams' original Alligator specification.
• Applied Price — default Median Price (high + low, divided by two), again matching the Alligator.

Changing any of these changes both indicators identically, since the Gator has no independent settings of its own — tuning it is tuning the Alligator, just read through a different lens.

Gator vs Alligator: Two Views of the Same Data

It's worth being precise about what the Gator adds, because it's easy to assume it's measuring something new. It isn't — the Alligator already contains every piece of information the Gator displays; three lines drawn on price already show whether they're tangled or fanned out. What the Gator changes is how quickly and reliably a trader can read that state. Judging "are these three lines tangled or separating" by eye works, but it's slower and more subjective than glancing at a histogram and asking "are these bars taller than the last few?" The Gator turns a visual judgment call into something closer to a simple rule, at the cost of not showing the actual price levels the Jaw, Teeth, and Lips sit at — for that, a trader still needs the Alligator itself plotted on the price chart alongside it.

Combining with Fractals and the Awesome Oscillator

The Gator inherits the same place in Bill Williams' broader system that the Alligator does, since it's really just an alternate readout of the same underlying lines. In the full system, Fractals mark candidate breakout levels, the Awesome Oscillator confirms momentum behind a breakout attempt, and the Alligator/Gator pair confirms whether the broader market is even in a trending state worth trading at all. A common sequence: wait for the Gator to show both histograms growing (confirming the Alligator has genuinely woken up, not just brushed against a false start), then take a Fractal breakout in the direction the fan and growth agree on, using the Awesome Oscillator as a final momentum check before committing.

A Word of Caution

The Gator carries the exact same lag the Alligator does, for the same reason — both are built from heavily smoothed SMMA lines shifted forward in time, so histogram growth confirms a trend is already underway rather than predicting one before it starts. A second, subtler trap: because both histograms are compared only to the bar right before them, a market chopping in a tight range can still occasionally produce a few bars of "growing" histograms without a real trend forming, especially right as the Alligator's lines are just beginning to separate from a tangle. Waiting for the fan order to be clearly established, not just the first bar or two of growth, filters out most of these false starts. As with the Alligator itself, the Gator says nothing about when a trend will end — pair it with a defined exit plan or a separate momentum check like the Awesome Oscillator rather than trading its growth signal in isolation.

Download the Indicator

This custom indicator plots the Gator Oscillator's upper and lower histograms and automatically alerts when both are growing together with a confirmed Alligator fan direction. It's available for both MetaTrader 4 and MetaTrader 5 below.

How to Install — MetaTrader 4

1. Download the gator-oscillator-alert.mq4 file below.
2. Open MetaTrader 4 → click File → Open Data Folder.
3. Place the file in the MQL4/Indicators folder.
4. Restart MetaTrader 4, then drag the indicator from the Navigator window onto the chart.

How to Install — MetaTrader 5

1. Download the gator-oscillator-alert.mq5 file below.
2. Open MetaTrader 5 → click File → Open Data Folder.
3. Place the file in the MQL5/Indicators folder.
4. Restart MetaTrader 5, then drag the indicator from the Navigator window onto the chart.

Both files are source code — open and review the full code before using it, for your own safety.