JSFiddle - React, Tailwind, and code Playground

HTML

<h2>Birds - Norwegian Yellow Finch</h2>
<h2>Cats - Domestic Shorthaired Tabby</h2>
<h2>Dogs - Alaskan Husky Cross - altul</h2>
<!--

1. You can place this code at the end of body, 
so it will be executed after all h2 tags rendering

-->
<!--
<script type="text/javascript">
    var re = /^[^-]+-\s*/,
        elements = document.getElementsByTagName('h2')

    function processText(el) {
        el.textContent = el.textContent.replace(re, '');
    }

    for(var i = 0, l = elements.length; i < l; i++) {
        processText(elements[i]);
    }
</script>
-->

<!--
2. Or place this code into external JavaScript file and include it at the end of body
<script type="text/javascript" src="/path/to/my/file.js" />
-->

JavaScript

// 3. Also you can execute it in window.onload event halder
    
var re = /^[^-]+-\s*/,
    elements = document.getElementsByTagName('h2')

function processText(el) {
    el.textContent = el.textContent.replace(re, '');
}

window.onload = function() {
    for(var i = 0, l = elements.length; i < l; i++) {
        processText(elements[i]);
    }
};