Magento: Get Sub category of current category

<?php 
$currentCat = Mage::registry('current_category');
$currentCatId = $currentCat->getId();
$collection = Mage::getModel('catalog/category')->load($currentCatId);
$subcats = $collection->getChildrenCategories();
?>
<?php 
<?php if(count($subcats) > 0) {
echo 'has sub';
}
?>