Almost with relief, he looked up at the sky.

They both picked up the distant insect drone of an aircraft engine beyond the towering cumulus clouds.  Here comes the spotter plane, he said quietly, and reached for the microphone of the radio.  Good morning, Sierra Mike.  We have you visual due south of our position approximately four miles.  I will give you yellow smoke.  Johnny nodded at one of his rangers, who pulled the tab on a smoke marker.

Sulphur-yellow smoke drifted in a heavy cloud across the treetops.

Roger, Parks.  I have your smoke.  Give me an indication on the target, please.

-" Johnny frowned at the word target and laid emphasis on the alternative word as he replied.  At sunset yesterday evening the herd was moving north towards the river five miles southeast of this position.  There are fifty-plus animals.  Thank you, Parks.  I will call again when we locate them.  They watched the aircraft bank away eastwards.  It was an ancient single-engined Cessna that had probably served on fireforce duties as a K-Car, or killer car, during the bush war.

Fifteen minutes later the radio crackled to life again.  Hello, Parks.

I have your herd.  Fifty-plus and eight miles from your present position.  The herd was spread out down both banks of a dry river-course that was gouged through a low line of flinty hills.  The forest was greener and more luxuriant here in the drainage where the deep roots had found subterranean water.  The acacia trees were in heavy pod.  The pods looked like long brown biscuits, clustered at the tips of the branches sixty feet above ground level.

Two cows moved in on one of the heavily laden trees.  They were the herd matriarchs, both of them over seventy years of age, gaunt old dowagers with tattered ears and rheumy eyes.

The bond between them was over half a century strong.  They were half-sisters, successive calves of the same mother.  The elder had been weaned at the birth of her sibling and had helped to nursemaid her as tenderly as would a human elder sister.  They had shared a long life, and had drawn from it a wealth of experience and wisdom to add to the deep ancestral instinct with which they had both been endowed at birth.

They had seen each other through drought and famine and sickness.

They had shared the joy of good rains and abundant food.  They knew all the secret hideaways in the mountains and the water-holes in the desert places.  They knew where the hunters lurked, and the boundaries of the sanctuaries within which they and the herd were secure.  They had played midwife to each other, leaving the herd together when the time was come upon one of them, and by their presence had fortified each other in the tearing agony of birth.  They had stripped the foetal sac from each other's newborn calves, and helped discipline them, instruct them and rear them to maturity.

Their own breeding days were long past, but the herd and its safety were still their duty and their main concern.  Their pleasure and their responsibility were the younger cows and the new calves that carried their own blood-lines.

Perhaps it was fanciful to endow brute animals with such human emotions as love and respect, or to believe that they understand blood relationships or the continuity of their line, but no one who had seen the old cows quieten the boisterous youngsters with raised ears and a sharp angry squeal, or watched the herd follow their lead with unquestioning obedience, could doubt their authority.  No one who had seen them caress the younger calves with a gentle trunk or lift them over the steep and difficult places on the elephant roads could question their concern.  When danger threatened they would push the young ones behind them and rush forward to the defence with ears spread wide and trunks rolled ready to fling out and strike down an enemy.

The great bulls with towering frames and massive girth might overshadow them in size, but not in cunning and ferocity.

The bulls tusks were longer and thicker, sometimes weighing well over one hundred pounds.  The two old cows had spindly misshapen ivory, worn and cracked and discoloured with age, and the bones showed through the scarred grey skin, but they were constant in their duty to the herd.

The bulls kept only a loose association with the breeding herd.  As they grew older they often preferred to break away and form smaller bachelor groups of two or three males, visiting the cows only when the heady scent of oestrus drew them in.  However, the old cows stayed with the herd.

They formed the solid foundation on which the social structure of the herd was based.  The tight-knit community of breeding cows and their calves relied heavily upon their wisdom and experience for its everyday needs and survival.

Now the two sisters moved in perfect accord to the giant acacia laden with seed pods, and each took up her position on either side of the trunk.  They laid their foreheads against the rough bark.  The trunk was over four feet in diameter, unyielding as a column of marble.  A hundred feet above the ground the high branches formed an intricate tracery and the pods and green leaves a cathedral dome against the sky.

The two old cows began to rock back and forth in unison with the tree-trunk between their foreheads.  At first the acacia was rigid, resisting even their great strength.  The cows worked on doggedly, pushing and heaving, first one then the other throwing her weight in opposite directions, and a tiny shudder ran up the tree and, high above them, the top branches trembled as though a breeze had passed.

Still they worked rhythmically and the trunk began to move.

A single ripe pod came loose from its twig and fell a hundred feet to crack against the skull of one of the cows.  She closed her watery old eyes tightly but never broke the rhythm of her heaves.  Between them the tree-trunk swayed and shuddered, ponderously at first and then more briskly.  Another pod and then another plopped down as heavily as the first drops of a thunderstorm.

The young animals of the herd realised what they were up to, they flapped their ears with excitement and hurried forward.  The acacia pods, rich in protein, were a favourite delicacy.  They crowded gleefully around the two cows, snatching up the scattering of pods as they fell and stuffing them far down their throats with their trunks.

By now the great tree was whipping back and forth, its branches waving wildly and its foliage thrashing.  The pods and loose twigs showered down thick as hail, rattling and bouncing from the backs of the elephants crowded beneath.

The two cows, still braced like a pair of book ends, kept doggedly at it until the shower of falling pods began to dry up.

Only when the last one was shaken from the branches did they step back from the tree-trunk.  Their backs were sprinkled with dead leaves and twigs, bits of dry bark and velvety pods, and they stood ankle-deep in the fallen debris.  They reached down and delicately picked out the golden pods with the dextrous fleshy tips of their trunks and curled them up into their gaping mouths, their triangular bottom lips drooping open.

The ooze from their facial glands wetting their cheeks like tears of pleasure, they began to feed.

The herd was pressed closely around them at the feast that they had laid.

As their long serpentine trunks swung and curled, and the pods were shovelled into their throats, there was a soft sound that seemed to reverberate through each of their great grey frames.  It was a gentle rumbling in many different keys, and the sound was interspersed with tiny creaking gurgling squeaks barely audible to the human ear.  it was a strangely contented chorus, in which even the youngest beasts joined.

It was a sound that seemed to express joy of life and to confirm the deep bond that linked all the members of the herd.